CIRCULAR

ISSUING THE "NATIONAL TECHNICAL REGULATION ON MOBILE RADIO EQUIPMENT WITH INTEGRAL ANTENNA FOR DATA AND SPEECH TRANSMISSION"

Pursuant to the Law on Standards and Technical Regulations dated June 29, 2006;

Pursuant to the Law on Telecommunications dated November 23, 2009;

WHEREAS, the Law on Radio Frequency Spectrum dated November 23, 2009;

WHEREAS, Decree No. 127/2007/NĐ-CP dated August 1, 2007 of the Government detailing and guiding the implementation of certain provisions of the Law on Technical Standards and Regulations;

Pursuant to Decree No. 78/2018/NĐ-CP dated May 16, 2018 of the Government amending and supplementing some articles of Decree No. 127/2007/NĐ-CP dated August 1, 2007 of the Government detailing the implementation of certain provisions of the Law on Standards and Technical Regulations;

Pursuant to Decree No. 17/2017/NĐ-CP dated February 17, 2017, issued by the Government, on the functions, tasks, powers, and organizational structure of the Ministry of Information and Communications;

Pursuant to the proposal of the Director of the Science and Technology Department,

The Minister of Information and Communications issues this Circular stipulating the National Technical Regulation on mobile radio equipment with integral antenna for data and speech transmission.

Article 1. Attached to this Circular is the National Technical Regulation on mobile radio equipment with integral antenna for data and speech transmission (QCVN 44:2018/BTTTT).

Article 2. Effective Date

1. This Circular shall take effect from July 1, 2019.

2. The National Technical Regulation on mobile radio equipment with integral antenna for data (and speech) transmission, designated QCVN 44:2011/BTTTT, as stipulated in Clause 3, Article 1 of Circular No. 26/2011/TT-BTTTT dated October 4, 2011 of the Minister of Information and Communications, ceases to be effective from July 1, 2019.

Article 3. The Director of the Office, Heads of Departments under the Ministry of Information and Communications, Heads of Provincial Departments of Information and Communications, and organizations and individuals related thereto shall be responsible for implementing this Circular.

 

QCVN 44:2018/BTTTT

AMENDMENT 1:2025 QCVN 07:2023/BXD

ON MOBILE RADIO EQUIPMENT WITH INTEGRAL ANTENNA FOR DATA AND SPEECH TRANSMISSION

National technical regulation

on land mobile radio equipment using an integral antenna intended for the transmission of data and speech

 

Table of Contents

Chapter 1. GENERAL PROVISIONS

1.1. Scope of Application

1.2. Applicability

1.3. Referenced Documents

1.4. Terms and Definitions

1.5. Abbreviations

Chapter 2. TECHNICAL PROVISIONS

2.1. General Requirements

2.1.1. Equipment to be measured

2.1.2. Measurement conditions, power supply, and ambient temperature

2.1.3. Other conditions

2.1.4. Interpretation of measurement results

2.2. Requirements for Transmitters

2.2.1. Frequency error

2.2.2. Effective radiated power

2.2.3. Power of adjacent and other channels

2.2.4. Spurious emissions

2.2.5. Transmitter activation time

2.2.6. Transmitter deactivation time

2.2.7. Transient effects of transmitters

2.3. Requirements for Receivers

2.3.1. Average receiver sensitivity (field strength, data or message)

2.3.2. Error effect when input signal level is high

2.3.3. Co-channel interference rejection

2.3.4. Adjacent channel selectivity

2.3.5. Spurious response rejection

2.3.6. Intermodulation spurious response rejection

2.3.7. Blocking characteristic

2.3.8. Spurious emissions

3. MANAGEMENT PROVISIONS

4. RESPONSIBILITIES OF ORGANIZATIONS AND INDIVIDUALS

Chapter 5. ORGANIZATION OF IMPLEMENTATION

Appendix A (Provisions) Field emission measurement

Appendix B (Provisions) Technical specifications for adjacent channel power measurement setup

LIST OF REFERENCES

 

Foreword

QCVN 44:2018/BTTTT replaces QCVN 44:2011/BTTTT.

QCVN 44:2018/BTTTT complies with standard ETSI EN 300 390 V2.1.1 (2016-03) of the European Telecommunications Standards Institute (ETSI).

QCVN 44:2018/BTTTT was compiled by the Post and Telecommunications Science and Technology Institute, reviewed by the Department of Science and Technology, and issued together with Circular No. /2018/TT-BTTTT dated December 2018.

 

AMENDMENT 1:2025 QCVN 07:2023/BXD

ON MOBILE RADIO EQUIPMENT WITH INTEGRAL ANTENNA FOR DATA AND SPEECH TRANSMISSION

National technical regulation

on land mobile radio equipment using an integral antenna intended for the transmission of data and speech

·1. GENERAL PROVISIONS

1.1. Scope of Application

This regulation sets technical requirements for terrestrial mobile radio equipment operating in the frequency band from 30 MHz to 1 GHz, with channel spacings of 12.5 kHz and 25 kHz.

Table 1 - Operating frequency band

This regulation applies to digital radio equipment, combined analog/digital radio equipment, using integral antennas for continuous or intermittent data and/or speech transmission.

1.2. Applicability

This regulation applies to Vietnamese and foreign organizations and individuals engaged in the production and business of equipment within the scope of regulation 1.1 throughout the territory of Vietnam.

1.3. Referenced Documents

ANSI C63.5 (2006): "American National Standard for Calibration of Antennas Used for Radiated Emission Measurements in Electro Magnetic Interference".

Recommendation ITU-T O.153 (10-1992): "Basic parameters for the measurement of error performance at bit rates below the primary rate".

ETSI TR 100 028 (V1.4.1) (12-2001) (all parts): "Electromagnetic compatibility and Radio spectrum Matters (ERM); Uncertainties in the measurement of mobile radio equipment characteristics".

ETSI TR 100 028-2 (V1.4.1) (12-2001): "Electromagnetic compatibility and Radio spectrum Matters (ERM); Uncertainties in the measurement of mobile radio equipment characteristics; Part 2".

ETSI EN 300 793 (V1.1.1): "Electromagnetic compatibility and Radio spectrum Matters (ERM); Land mobile service; Presentation of equipment for type testing".

ETSI TR 102 273 (V1.2.1) (all parts): "Electromagnetic compatibility and Radio spectrum Matters (ERM); Improvement on Radiated Methods of Measurement (using test site) and evaluation of the corresponding measurement uncertainties".

1.4. Terms and Definitions

1.4.1. Integral antenna (integral antenna)

An antenna designed to connect directly to the equipment without using a 50 Ω external antenna connector and considered part of the equipment. Integral antennas may be installed inside or outside the equipment.

1.4.2. Conducted measurements

Measurements using direct RF connection to the equipment under test.

1.4.3. Radiated measurements

Absolute measurements of field strength.

1.4.4. Base station (base station)

Radio equipment with an antenna connector for connecting to an external antenna and used in a fixed location.

1.4.5. Mobile station (mobile station)

Mobile radio equipment with an antenna connector for connecting to an external antenna, typically used on transport vehicles or portable devices.

1.4.6. Handheld station (handportable station)

Radio equipment with an antenna connector or integral antenna, or both, typically used independently, carried on the person or handheld.

1.4.7. Adjacent and alternate channels (adjacent and alternate channels)

- Adjacent channel: Two channels offset from the desired channel by one channel spacing.

- Alternate channel: Two channels offset from the desired channel by two channel spacings.

1.5. Abbreviations

In cases where the equipment has an integrated antenna and there is no fixed 50 Ω connector, a second sample with a temporary antenna connector may be used for easier testing. No matching device should be used for radiation measurements.

2.1. General Requirements

2.1.1. Equipment to be measured

The specifications of the equipment to be measured must represent the specifications of the corresponding product sample.

NOTE: Specific guidance can be found in ETSI EN 300 793.

2.1.2.1. Normal and Limit Measurement Conditions

Measurements must be carried out under normal measurement conditions and, if indicated, at limit measurement conditions.

2.1.2.2. Measurement Power Supply

During measurement, the equipment's power supply must be replaced with a measurement power supply capable of providing normal and limit voltages as specified in Sections 2.1.2.3.2 and 2.1.2.4.2. The pure internal resistance of the measurement power supply must be sufficiently low to not significantly affect the measurement results. For measurement purposes, the power supply voltage must be measured at the equipment's input.

2.1.2. Measurement conditions, power supply, and ambient temperature

If the equipment has a power supply cable, the measurement voltage must be the voltage measured at the point where the power supply cable connects to the equipment.

For equipment using batteries, the batteries must be removed and the measurement power supply must have technical specifications similar to the actual battery.

During measurement, the power supply voltages must have a tolerance of ±1% relative to the voltage at the start of each measurement. This tolerance value is the limit for power supply measurements.

2.1.2.3. Normal Measurement Conditions

2.1.2.3.1. Normal Temperature and Humidity

The normal temperature and humidity conditions during measurement are within the following ranges:

- Temperature: +15°C to +35°C;

- Relative Humidity: 20% to 75%.

2.1.2.3.2. Normal Measurement Power Supply Voltage

a. Grid Voltage

The normal measurement voltage for equipment connected to the grid must be the nominal grid voltage. In this Standard, the nominal voltage is the published voltage or any voltage designed for the equipment.^°The frequency of the AC power supply measurement voltage must be between 49 Hz and 51 Hz.^°b. Lead-Acid Battery Power Supply Used on Transport Vehicles

When radio equipment uses lead-acid batteries on transport vehicles, the normal measurement voltage is 1.1 times the nominal battery voltage.

c. Other Power Supplies

When other types of power supplies or batteries are used, the normal measurement voltage must be the voltage published by the manufacturer.

2.1.2.4. Limit Measurement Conditions

2.1.2.4.1. Limit Temperature

At limit temperatures, measurements must be conducted according to the procedures in Section 2.2.1.3 at higher and lower temperatures than the following range: -20°C to +55°C.

With reference to Table 3, Section 2.2.1.2, the additional limit temperature range has been reduced to 0°C to +30°C and is used when the equipment does not meet the requirements in Table 3 with a limit temperature range of -20°C to +55°C.

Measurement reports must clearly state the temperature range used.

2.1.2.4.2. Limit Measurement Power Supply Voltages

The limit measurement voltage for equipment connected to AC power supply must be the nominal grid voltage ±10%.

When using equipment on transport vehicles with lead-acid batteries, the normal measurement voltage is 1.3 times and 0.9 times the nominal battery voltage (6V, 12V...).

c. Power Supplies Using Other Types of Batteries^°The lower limit voltage for equipment with battery power supplies is as follows:^°4. Liquid bull semen

- For Leclanche or Lithium batteries: 0.85 times the nominal battery voltage.^°- For Mercury or Nickel-Cadmium batteries: 0.9 times the nominal battery voltage.^°There is no upper limit measurement voltage.^°The lower limit voltage for equipment with battery power supplies is as follows:^°4. Liquid bull semen

In cases where the upper limit test voltage is not applied, the four corresponding test conditions are:

d. Other Power Supplies

When other types of power supplies or batteries are used, the normal measurement voltage must be the voltage published by the manufacturer.

For equipment using other types of power supplies or batteries, the limit measurement voltage must be the voltage selected by the manufacturer or agreed upon between the manufacturer and the testing laboratory. This must be recorded in the measurement report.

At limit temperatures, measurements must be conducted according to the procedures in Section 2.2.1.3 at higher and lower temperatures than the following range: -20°C to +55°C.

2.1.2.5. Measurement Procedures at Limit Temperatures

Before conducting measurements, the equipment must reach thermal equilibrium in the measurement room. The equipment must be turned off during the temperature stabilization period.

In cases where the equipment has a continuous operation temperature stabilization circuit, these circuits must be turned on for 15 minutes after reaching thermal equilibrium and then the equipment must meet the specified requirements. For such equipment, the manufacturer must provide an independent power supply circuit for the internal crystal oscillator, which is separate from the power supply to the rest of the equipment.

If thermal equilibrium cannot be verified through measurements, the temperature stabilization time must be at least 1 hour or longer as determined by the testing laboratory.

The measurement procedure must be chosen and the room humidity adjusted so that condensation does not occur.

2.1.2.5.1. Measurement Procedures for Continuous Operation Equipment

If the manufacturer states that the equipment is designed for continuous operation, the measurement procedure is as follows:

V_{Maximum Downhill Gradient}/T_{Maximum Downhill Gradient}for each specific service package in the service provision contract between the ISP and the customer._{Maximum Downhill Gradient}/T_max

V_max/T_{Maximum Downhill Gradient}for each specific service package in the service provision contract between the ISP and the customer._max/T_max

- Prior to measuring at upper limit temperatures, the equipment must be placed in the measurement room until it reaches thermal equilibrium. Then turn on the equipment in transmission mode for 30 minutes, after which the equipment must meet the specified requirements.

For devices using other power sources or batteries, the limit voltage must be the voltage selected by the manufacturer or agreed upon between the device manufacturer and the testing laboratory. This must be recorded in the measurement report.

2.1.2.5. Measurement procedures at limit temperatures

Prior to conducting the measurements, the device must achieve thermal equilibrium in the measurement room. The device must be turned off during the temperature stabilization period.

In cases where the device has a continuous operation temperature stabilization circuit, these temperature stabilization circuits must be activated for 15 minutes after achieving thermal equilibrium, and then the device must meet the specified requirements. For such devices, the manufacturer must provide an independent oscillator crystal power supply circuit that is separate from the power source supplied to the rest of the device.

If thermal equilibrium cannot be verified through measurements, the temperature stabilization time must be at least 1 hour or longer as determined by the testing laboratory.

The measurement sequence must be chosen and the humidity in the measurement room adjusted so that condensation does not occur.

2.1.2.5.1. Measurement procedure for continuously operating devices

If the manufacturer states that the device is designed for continuous operation, the measurement procedure shall be as follows:

- Before measuring at limit temperatures, the device must be placed in the measurement room until it reaches thermal equilibrium. Then, turn on the device in the transmit state for 30 minutes; after this time, the device must meet the specified requirements.

- Prior to measuring at sub-limit temperatures, the device must be placed in the measurement room until thermal equilibrium is achieved, then transitioned to standby or off state for 1 minute. After this time, the device must meet the specified requirements.

2.1.2.5.2. Measurement procedures for non-continuous operation devices

If the manufacturer declares that the device is designed for intermittent operation, the measurement procedure shall be as follows:

- Prior to measuring at upper limit temperatures, the device must be placed in the measurement room until thermal equilibrium is achieved. Then, turn on the device in the transmit state for 1 minute, followed by 4 minutes in the receive state. After this time, the device must meet the specified requirements.

- Prior to measuring at sub-limit temperatures, the device must be placed in the measurement room until thermal equilibrium is achieved, then transitioned to standby or off state for 1 minute. After this time, the device must meet the specified requirements.

2.1.3. Other conditions

2.1.3.1. Normal measurement signals (desired and undesired signals)

Desired signals for measurement methods with bit streams and messages defined in Sections 2.1.3.1.1 and 2.1.3.1.2.

Signal A-M3 is used as an undesired signal for measurement methods with bit streams or messages such as co-channel interference and adjacent channel selectivity. This signal is defined as follows:

Signal A-M3 consists of an RF signal modulated by a 1_kHz voice frequency signal with a deviation of 12% from the channel spacing.

2.1.3.1.1. Signals for bit stream measurements

When the device is designed to continuously transmit bit streams (data, fax, image transmission, digital voice), normal measurement signals are as follows:

- Signal D-M0, consisting of an infinite series of 0 bits;

- Signal D-M1, consisting of an infinite series of 1 bits;

- Signal D-M2, consisting of a pseudo-random bit sequence with at least 511 bits according to ITU-T O.153 recommendations;

- Signal D-M2', having a similar format to D-M2, but with an independent pseudo-random bit sequence compared to D-M2 (which may be identical to D-M2 but starting at a different point in time);

An infinite series of 0 or 1 bits usually does not have a characteristic bandwidth. Signal D-M2 is used to approximate the characteristic bandwidth.

2.1.3.1.2. Signals for message measurements

When the measured device uses messages, normal measurement signals will be a series of messages or correctly encoded bits.

Normal modulation signals will be achieved as follows:

- Signal D-M3, corresponding to single clusters, is used in up-down measurement methods, stimulated manually or by automatic measurement systems;

- Signal D-M4, consisting of correctly encoded signals, messages transmitted sequentially, one message at a time, without intervals between messages.

D-M3 is used for receiver measurement methods with messages, where it is necessary to transmit single messages multiple times. The corresponding normal modulation must be agreed upon between the manufacturer and the testing laboratory.

Signal D-M4 is used for transmitter measurement methods such as adjacent channel power and spurious emission.

Details of signals D-M3 and D-M4 must be recorded in the measurement report.

2.1.3.2. Dummy antennas

Transmitter measurements using a test set must be performed with a 50 Ω non-radiating, non-reflective termination connected to the end of the test set.

2.1.3.3. Arrangement of measurement signals to the receiver input through the test set and dummy antenna

The measurement signal source is connected to the receiver input through the test set and dummy antenna such that the impedance of the test set and the dummy antenna are both 50 Ω. This requirement must be met even when one or more measurement signals are simultaneously applied to the receiver via a combined network.

Measurement signal levels are represented by the emf at the output of the test signal source.

Any influence of cross-modulation noise and noise generated within the measurement signal sources must be negligible.

2.1.4. Interpretation of measurement results

The interpretation of recorded measurement results is as follows:

- Measured values compared to corresponding limits will be used to determine whether the device meets the requirements of this Standard.

- The actual measurement uncertainty of each measured parameter must be recorded in the measurement report.

- The value of the actual measurement uncertainty must be equal to or less than the values in Table 2 (absolute measurement uncertainty: maximum values).

For the measurement methods in this Standard, calculating the measurement uncertainty values with the corresponding coverage factors is k = 1.96 or k = 2 (these coverage factors correspond to confidence levels of 95% and 95.45%, respectively, assuming a Gaussian (Gaussian) distribution of the actual measurement uncertainties). Calculations of measurement uncertainty values comply with ETSI TR 100 028.

Table 2 - Absolute measurement uncertainty: maximum values

2.2. Requirements for Transmitters

2.2.1. Frequency error

2.2.1.1. Definitions

The transmitter frequency error is the difference between the measured carrier frequency before modulation and the transmitter's nominal frequency.

2.2.1.2. Limits

The frequency error must not exceed the values specified in Table 3 under normal, limit, or any intermediate measurement conditions.

Table 3 - Frequency Error

Figure 1 - Frequency Error Measurement Diagram

Place the device to be measured in the test set (Section A.4), connect the test set to the dummy antenna (see 2.1.3.2). Measure the carrier frequency before modulation.

The measurement must be performed under normal measurement conditions (see 2.1.2.3) and limit measurement conditions (applying both 2.1.2.4.1 and 2.1.2.4.2).

Measurements must be performed under normal measurement conditions (see 2.1.2.3) and limit measurement conditions (applying both 2.1.2.4.1 and 2.1.2.4.2 simultaneously).

2.2.2. Effective radiated power

The management agency may publish the maximum effective radiation power of the transmitter; this may be a condition for issuing a certificate.

If the device is designed to operate with different carrier powers, the maximum effective radiation power at each level or range of levels will be published by the manufacturer. Users cannot intervene to adjust this power.

The technical requirements in this Standard must meet all operating power levels of the transmitter. In practice, measurements are only carried out at the highest and lowest power levels of the transmitter.

2.2.2.1. Definition

The maximum effective radiation power is defined as the effective radiation power in the direction of the maximum field strength under the specified measurement conditions.

The rated maximum effective radiation power is the maximum effective radiation power published by the manufacturer.

The average effective radiation power is the average value of the effective radiation power measured in eight directions.

The rated average effective radiation power of the device is also published by the manufacturer.

2.2.2.2. Limits

2.2.2.2.1. Effective Radiation Power under Normal Measurement Conditions

The maximum effective radiation power under normal measurement conditions must be within the range d_f compared to the rated maximum effective radiation power.

The average effective radiation power under normal measurement conditions must be within the range d_f compared to the rated average effective radiation power.

The characteristic error of the equipment (± 1.5 dB) will be combined with the actual measurement uncertainty to calculate d_f as follows:

For coal-fired thermal power plants where the enterprise holds 100% of the registered capital and uses 100% of its own capital to invest in the project approved by the competent authority, E is determined as 100%;_f² = d_{Granite, gabbro, decorative stone...}² + d_{Average loan repayment period is 10 years;}²

Where: d_{Granite, gabbro, decorative stone...} is the actual measurement uncertainty.

For coal-fired thermal power plants where the enterprise holds 100% of the registered capital and uses 100% of its own capital to invest in the project approved by the competent authority, E is determined as 100%;_{Average loan repayment period is 10 years;} is the permissible equipment error (± 1.5 dB).

For coal-fired thermal power plants where the enterprise holds 100% of the registered capital and uses 100% of its own capital to invest in the project approved by the competent authority, E is determined as 100%;_f is the total error.

All values must be expressed in linear form.

In all cases, the measurement uncertainty must comply with 2.1.5, Table 2.

Additionally, the maximum effective radiation power must not exceed the maximum value prescribed by the management agency.

2.2.2.2.2. Effective Radiation Power under Limit Measurement Conditions

The power variation due to temperature and voltage changes during measurements under limit conditions must not exceed +2 dB or -3 dB.

2.2.2.3. Measurement Methods

2.2.2.3.1. Maximum Effective Radiation Power under Normal Measurement Conditions

i. The measurement position must meet the bandwidth requirements of the measurement. First, the measuring antenna is oriented vertically polarized unless otherwise indicated. Place the transmitter to be measured at the standard position and turn it on in the unmodulated mode.

ii. Adjust the frequency of the spectrum analyzer or measuring receiver to the carrier frequency of the transmitter. Adjust the height of the measuring antenna within the specified height range until the maximum signal level is obtained on the spectrum analyzer or selected frequency voltmeter.

iii. Rotate the transmitter 360⁰ around the vertical axis until a higher signal or the "highest" maximum signal is obtained.

Figure 2 - Diagram for Measuring Effective Radiation Power under Normal Measurement Conditions

iv. Adjust the measuring antenna up or down once more within the specified height range until a new maximum signal level is obtained. Record this level. This maximum signal level may be lower than the value that could be achieved at heights outside the specified limits. The measuring antenna may not need to be adjusted in height if the measurement is performed at a non-reflective room measurement position (section A.1.2).

Figure 3 - Diagram for Measuring Effective Radiation Power Using a Substitute Antenna

v. Using the measurement diagram shown in Figure 3, a substitute antenna is used instead of the transmitter antenna at the same position and with the same vertical polarization. Adjust the frequency of the signal generator to the carrier frequency of the transmitter. The measuring antenna must be adjusted up or down to ensure the maximum signal is still obtained.

Adjust the signal level at the substitute antenna until the receiver measures a level equivalent to that of the transmitter or a level corresponding to a known correlation.

The maximum effective radiated power value of the device to be measured is equivalent to the transmission power of the signal generator after being increased according to a known correlation if necessary, and after additional calibration for the gain of the substitute antenna and loss due to the cable between the signal generator and the substitute antenna.

vi. Repeat steps from ii. to v. above with the measurement antenna and the horizontally polarized substitute antenna.

vii. The maximum effective radiated power of the device to be measured will be represented by the higher value found in step v.

2.2.2.3.2. Average Effective Radiated Power under Normal Measurement Conditions.

i. Repeat the procedures from steps ii. to v. in Section 2.2.2.3.1, except in step iii., the transmitter will be rotated to eight different positions, spaced 45 degrees apart.⁰ starting from the position corresponding to the maximum effective radiated power (see Section 2.2.2.3.1, step vii.).

ii. The average effective radiated power corresponding to the eight measurements above is calculated as follows:

Average Effective Radiated Power = 8

where Pi is the power measured at each position.

2.2.2.3.3. Method for Measuring Average and Maximum Effective Radiated Power under Limit Measurement Conditions.

Figure 4 - Diagram for measuring average and maximum effective radiated power under limit measurement conditions.

i. Measurements must also be performed under limit measurement conditions. Since it is not possible to repeat the measurement at the measurement location under limit temperature conditions, only relative measurements using a test set are performed.

ii. The power supplied to the load is measured under normal and limit measurement conditions. The difference value is calculated in dB. This difference value is algebraically added to the average effective radiated power under normal measurement conditions to calculate the average radiated power under limit measurement conditions.

iii. Similarly, the maximum effective radiated power can be calculated.

iv. Under limit measurement conditions, additional uncertainty may arise due to calibration of the test set.

§2.2.3. Adjacent Channel and Other Channel Power

·2.2.3.1. Definition

Adjacent channel power is a portion of the total output power of the transmitter under specified modulation conditions within a defined bandwidth, with a central frequency being the nominal frequency of one of the two adjacent channels. This power is the sum of the average power generated by modulation, noise, and other unwanted emissions of the transmitter.

·2.2.3.2. Limits

For a channel spacing of 25 kHz, the adjacent channel power must be at least 70 dB lower than the carrier power of the transmitter, and the adjacent channel power does not necessarily have to be lower than 0.2 μW.

For a channel spacing of 12.5 kHz, the adjacent channel power must be at least 60 dB lower than the carrier power of the transmitter, and the adjacent channel power does not necessarily have to be lower than 0.2 μW.

In cases where the equipment cannot generate an unmodulated carrier wave, these measurements will be carried out under limit measurement conditions. Under limit measurement conditions, the measured adjacent channel power shall not exceed:

- 65 dB compared to the carrier power of the equipment with a channel spacing of 25 kHz.

- 55 dB for a channel spacing of 12.5 kHz.

·2.2.3.3. Measurement Method

Figure 5 - Diagram for measuring adjacent channel and other channel power

i. Place the transmitter to be measured in the test set (Section A.4) connected to the power meter receiver through a dummy antenna (see 2.1.3.2). Calibrate the power meter receiver to measure the rms power level. The level at the input of the power meter receiver must be within the allowable limits. The transmitter must operate at the maximum permissible carrier power level.

ii. For unmodulated transmitters, adjust the power meter receiver to obtain maximum response. This is the 0 dB response point. Record the attenuation setting of the power meter receiver.

iii. Adjust the frequency of the power meter receiver off the carrier such that a -6 dB response is obtained at the frequency closest to the carrier frequency of the transmitter, which corresponds to the frequency deviation from the nominal carrier frequency as given in Table 4.

Table 4 - Frequency Shift

iv. Modulate the transmitter with measurement signals D-M2 or D-M4 (see 2.1.3.1).

v. Adjust the variable attenuator of the power meter receiver to obtain the same power value as in step ii. Record this value.

vi. The ratio of adjacent channel power to carrier power is the difference between the attenuation settings in steps ii. and v. The absolute value of the adjacent channel power can be calculated from this ratio and the carrier power of the transmitter.

vii. Repeat the measurements from step iii. to vi. with the power meter receiver adjusted to the opposite side of the carrier.

viii. Repeat the measurements for other channels.

ix. For devices unable to generate an unmodulated carrier wave, repeat the measurements under limit measurement conditions (apply simultaneously see 2.1.2.4.1 and 2.1.2.4.2.).

2.2.4. Spurious emissions

2.2.4.1. Definition

Spurious emissions are emissions from the transmitter's antenna and housing at frequencies other than the carrier frequency and normal modulation sidebands.

Spurious emissions are defined as the power of any discrete signal.

2.2.4.2. Limits

The power of spurious emissions shall not exceed the values in Table 5.

Table 5 - Spurious Emissions Power

Reference parameters are presented in Tables 6 and 7.

Table 6 - Bandwidth Used in Spurious Emission Measurement

Table 7 - Bandwidth Used at Desired Emission Level

2.2.4.3. Measurement Method

i. The measurement position must meet the bandwidth requirements specified for the measurement. The test antenna will be oriented vertically polarized and connected to a spectrum analyzer or receiver through an appropriate filter to avoid overloading the receiver. The bandwidth of the spectrum analyzer will be selected within the range of 10 kHz to 100 kHz, set to an appropriate value to perform accurate measurements. To measure the out-of-band emissions below the second harmonic of the carrier frequency, a high "Q" filter with a center frequency similar to that of the transmitter's carrier frequency and at least 30 dB signal attenuation should be used. For measuring out-of-band emissions at and above the second harmonic of the carrier frequency, a high-pass filter with a stopband attenuation greater than 40 dB should be used. The cutoff frequency of the high-pass filter should be approximately 1.5 times the transmitter's carrier frequency. The transmitter to be measured shall be placed on a stand at the standard position and turned on in the unmodulated state. If the unmodulated carrier cannot be obtained, the measurement shall be performed with the transmitter modulated by the D-M2 or D-M4 signal.

Figure 6 - Diagram for Measuring Spurious Emission Radiation

ii. The radiation of any out-of-band emission in the frequency band from 30 MHz to 4 GHz shall be determined by the measurement antenna and spectrum analyzer or frequency-selective voltmeter excluding the channel where the transmitter operates and adjacent channels. Additionally, for equipment operating at frequencies above 470 MHz, measurements shall be repeated in the frequency band from 4 GHz to 12.75 GHz. Record the frequency of each detected out-of-band emission. If the measurement position is interfered with by external noise, the measurement must be carried out in a shielded room with the distance between the transmitter and the measurement antenna shortened.

iii. At each frequency where an emission has been detected, adjust the spectrum analyzer and the height of the measurement antenna within the prescribed height range until the maximum signal level is obtained on the spectrum analyzer.

iv. Rotate the transmitter 360 degrees around the vertical axis until the maximum signal level is obtained on the spectrum analyzer.⁰ degrees around the vertical axis until the maximum signal level is obtained on the spectrum analyzer.

v. Adjust the height of the measurement antenna again within the prescribed height range to find the new maximum reception level. Record this signal level.

vi. Using the measurement diagram as shown in Figure 7, replace the transmitter antenna with a substitute antenna at the same position and vertical polarization. Connect the substitute antenna to the signal generator.

vii. At each frequency where an emission has been detected, adjust the signal generator, substitute antenna, and spectrum analyzer to the emission frequency, adjust the height of the measurement antenna within the prescribed range until the maximum signal level is obtained on the spectrum analyzer or frequency-selective voltmeter.

Record the signal level of the signal generator on the spectrum analyzer similarly to item e) above. After adjusting for the gain of the substitute antenna and cable loss between the substitute antenna and the main signal generator, this value is the spurious emission radiation level at this frequency.

The resolution bandwidth of the measurement device is the smallest available bandwidth, but larger than the bandwidth of the spurious emission component to be measured.

viii. Repeat the measurements with the measurement antenna in horizontal polarization from step iii. to vii. above.

ix. Repeat the measurements from iii. to viii. above with the transmitter in standby mode (if applicable).

Figure 7 - Measurement Diagram for Measuring Spurious Emission Radiation Using a Substitute Antenna

2.2.5. Transmitter activation time

2.2.5.1. Definitions

The transmitter activation time (t_a) is the time interval between the moment "turning on the transmitter" (T_on) and:

- The moment when the output power of the transmitter reaches a level less than 1 dB or more than 1.5 dB of the steady-state power (P_of) and maintains within the range of +1.5 dB/-1 dB relative to P_of, as observed on the measuring instrument or power/time graph; or:

- The moment when the carrier frequency remains within ± 1 kHz of the steady-state frequency F_of, as observed on the measuring instrument or frequency/time graph.

The measured value of t_a is t_{1 ||| I hereby issue this Circular to amend and supplement certain provisions on periodic reporting regimes in Circulars issued by the Minister of Industry and Trade or jointly issued, which shall take effect from February 5, 2020;}; the limit is t_al.

2.2.5.2. Limits

The time t_{1 ||| I hereby issue this Circular to amend and supplement certain provisions on periodic reporting regimes in Circulars issued by the Minister of Industry and Trade or jointly issued, which shall take effect from February 5, 2020;} (measured transmitter activation time) shall not exceed 25 ms (t_{1 ||| I hereby issue this Circular to amend and supplement certain provisions on periodic reporting regimes in Circulars issued by the Minister of Industry and Trade or jointly issued, which shall take effect from February 5, 2020;} ≤ t_al).

2.2.5.3. Measurement Method

The measurement diagram as shown in Figure 8.

Figure 8 - Measurement Diagram for Transmitter Power and Frequency Transition Response, including Activation Time and Deactivation Time

i. Place the transmitter to be measured into the measurement coupler connected to the RF splitter and discriminator through an appropriate load. The load attenuation is chosen such that the input of the discriminator is protected against overload and the limited amplifier of the discriminator operates accurately within its range when the transmitter's carrier power (before attenuation) exceeds 1 mW.

The two-channel memory oscilloscope (or transient recorder) records the transition amplitude from the splitter according to the logarithmic scale and records the transition frequency from the discriminator.

The trigger ensures that the sweep start time of the oscilloscope begins immediately after the "turning on the transmitter".

ii. The sweep chart of the oscilloscope is calibrated according to power and frequency (Y-axis) and according to time (X-axis) using a signal generator.

iii. The transmitter activation time is measured directly on the oscilloscope while the transmitter is unmodulated.

2.2.6. Transmitter deactivation time

Customer assistance service is a service that provides answers to inquiries, advice, guidance on using the service, accepts requests, and provides information to customers about IPTV services on the fixed terrestrial telecommunications network.

The transmitter deactivation time (t_F) is the time interval between the moment "turning off the transmitter" (T_off) and the moment when the output power of the transmitter drops below the steady-state power (P_of) by 50 dB and remains below this level as observed on the measuring instrument or power/time graph (Figure 11).

The measured value of t_F is t_rm; the limit is t_rl.

2.2.6.2. Limits

The transmitter deactivation time (t_rm) shall not exceed 20 ms (t_rm ≤ t_rl).

2.2.6.3. Measurement Method

The measurement diagram as shown in Figure 8.

i. Place the transmitter to be measured into the measurement coupler connected to the RF splitter and discriminator through an appropriate load. The load attenuation is chosen such that the input of the discriminator is protected against overload and the limited amplifier of the discriminator operates accurately within its range when the transmitter's carrier power (before attenuation) exceeds 1 mW.

The dual-channel memory oscilloscope (or transient recorder) records the transition amplitude (transition) from the splitter according to the logarithmic scale and records the transition frequency from the discriminator.

The trigger ensures that the sweep start time of the oscilloscope is initiated immediately after "turning on the transmitter".

ii. The traces of the oscilloscope are calibrated according to power and frequency (Y-axis) and according to time (X-axis) by replacing the transmitter and load with a signal generator.

iii. The deactivation time of the transmitter is measured directly on the oscilloscope while the transmitter is not modulated.

2.2.7. Transient effects of transmitters

2.2.7.1. Definition

The transient effect of the transmitter is the time dependency of the transmitter frequency, power, and adjacent channel power when turning on and off the RF output power.

The powers, frequencies, frequency tolerances, and transient times are defined as follows:

"5. The pre-tax weighted average cost of capital i (%) is determined according to the formula below:₀: Rated power;

"5. The pre-tax weighted average cost of capital i (%) is determined according to the formula below:_of: Stable state power;

"5. The pre-tax weighted average cost of capital i (%) is determined according to the formula below:_a: Adjacent channel transient power. This is the transient power in adjacent channels due to turning on and off the transmitter;

F_°: Carrier frequency rated;

F_of: Stable state carrier frequency;

For coal-fired thermal power plants where the enterprise holds 100% of the registered capital and uses 100% of its own capital to invest in the project approved by the competent authority, E is determined as 100%;_f: Frequency deviation (relative to F_of) or absolute frequency error (see 2.2.1.1) of the transmitter;

df_{Average loan repayment period is 10 years;}: Limit of the frequency error (d_f) in stable state (see 2.2.1.2);

df_°: Limit of the frequency deviation (d_f) equal to 1 kHz. If modulation cannot be turned off, an additional half-channel spacing must be added;

df_of: Limit of the frequency deviation (d_f) during the transient period, equal to 1/2 channel spacing; When the frequency deviation is less than df_of-, the carrier frequency remains within the assigned channel range. If modulation cannot be turned off, an additional 1/2 channel spacing must be added;

Voltage Standing Wave Ratio_on: Transmitter turn-on time;

organize credit institutions, foreign bank branches are responsible for organizing the implementation of this Circular._on: Time when the carrier power exceeds (P_of) - 30 dB;

organize credit institutions, foreign bank branches are responsible for organizing the implementation of this Circular._p: Time interval starting from t_on and ending when the power reaches (P_of) - 6 dB;

organize credit institutions, foreign bank branches are responsible for organizing the implementation of this Circular._{1 ||| I hereby issue this Circular to amend and supplement certain provisions on periodic reporting regimes in Circulars issued by the Minister of Industry and Trade or jointly issued, which shall take effect from February 5, 2020;}: Transmitter activation time as defined in Section 2.2.5.1;

organize credit institutions, foreign bank branches are responsible for organizing the implementation of this Circular._al: Limit of t_{1 ||| I hereby issue this Circular to amend and supplement certain provisions on periodic reporting regimes in Circulars issued by the Minister of Industry and Trade or jointly issued, which shall take effect from February 5, 2020;} as in Section 2.2.5.2;

Voltage Standing Wave Ratio_off: Transmitter turn-off time;

d.1. Amount of taxable income in Vietnam:_off: Time when the carrier power drops below (P_of) - 30 dB;

organize credit institutions, foreign bank branches are responsible for organizing the implementation of this Circular._{For coal-fired thermal power plants where the enterprise holds 100% of the registered capital and uses 100% of its own capital to invest in the project approved by the competent authority, E is determined as 100%;}: Time interval starting when the power drops below (P_of) - 6 dB and ending at t_off;

organize credit institutions, foreign bank branches are responsible for organizing the implementation of this Circular._rm: Transmitter deactivation time as defined in Section 2.2.6.1, after which the power maintains a level lower than (P_of) - 50 dB;

organize credit institutions, foreign bank branches are responsible for organizing the implementation of this Circular._rl: Limit of t_rm as in Section 2.2.6.2.

If a synthesizer or/and phase-locked loop (PLL) system is used to determine the transmitter frequency, the transmitter must turn off upon loss of synchronization or, in the case of using PLL, when the loop does not lock.

2.2.7.2. Timing, Frequency, and Power

Figures 9, 10, and 11 illustrate the timing, frequency, and power as defined in Sections 2.2.5.1, 2.2.6.1, 2.2.7.1, and comply with the limits specified in Sections 2.2.5.2, 2.2.6.2, and 2.2.7.3.

2.2.7.3. Limits

2.2.7.3.1. Time Domain Analysis of Power and Frequency

The graphs of carrier power and carrier frequency over time, including several transient values, must be recorded in the measurement report.

At any point where the carrier power is greater than the stable state power (P_of) - 30 dB, the carrier frequency will remain within a half-channel spacing (df_of) from the stable state carrier frequency (F_of).

The slopes of the corresponding graphs for both activation and deactivation times must satisfy:

- t_p ≥ 0.20 ms and t_{For coal-fired thermal power plants where the enterprise holds 100% of the registered capital and uses 100% of its own capital to invest in the project approved by the competent authority, E is determined as 100%;} ≥ 0.20 ms, for activation and deactivation times (see 2.2.7.1);

- Between points (P_of) - 30 dB and (P_of) - 6 dB, in both activation and deactivation cases, the slope must not change.

2.2.7.3.2. Adjacent Channel Transient Power

The adjacent channel transient power shall not exceed the following value:

- Lower than 60 dB relative to the transmitter carrier power (dBc) without necessarily being lower than 2 μW (-27.0 dBm), for 25 kHz channel spacing;

- Lower than 50 dBc without necessarily being lower than 2 μW (-27.0 dBm), for 12.5 kHz channel spacing.

2.2.7.4. Measurement Method

The transmitter to be measured must be placed in the test setup (Section A.4).

Figure 9 - Transmitter activation time and transient effects when turning on

(Effects of power increase during transmitter activation)

Figure 10 - Transmitter activation time and transient effects during turning on

(Transient effects of frequency when turning on)

Figure 11 - Transmitter deactivation time and transient effects during turning off

The transient times (switching on and off points) and frequency deviations appearing in these cycles can be measured by spectrum analyzers and discriminators that meet the requirements specified in Section 2.2.7.3.2.

2.2.7.4.1. Frequency and Time Domain Measurements

i. Perform measurements on the unmodulated transmitter.

ii. The measurement setup is configured as shown in Figure 12. The transmitter to be measured is placed in the test setup.

iii. Check the calibration of the measuring equipment. The output of the test setup is connected to the input of the spectrum analyzer and discriminator through power attenuators and power dividers.

iv. The value of the power attenuator is selected such that the input of the measuring equipment is protected against overload and the limited amplifier of the discriminator operates accurately within its limit range under the conditions of power according to 2.2.7.1.

v. The spectrum analyzer is set up to measure and display power over time.

vi. Calibrate the discriminator. This is done by applying RF voltages from the signal generator with specific frequency deviations from the rated frequency of the transmitter.

vii. Use appropriate equipment to generate trigger pulses for the measuring equipment when turning on and off the transmitter.

viii. Monitor the turning on and off of the RF power.

ix. The voltage at the discriminator output is recorded as a function of time corresponding to the power level on the memory device or overshoot recorder. This voltage measures the frequency deviation. The transient frequency intervals can be measured using the time base of the memory device. The discriminator output is valid only after t_on and before t_off.

2.2.7.4.2. Measurement Setup and Discriminator Characteristics

Figure 12 - Measurement setup for the transient effects of power and frequency of the transmitter during activation and deactivation times

The discriminator may include a mixer and an internal oscillator (subcarrier generator) to convert the measured transmitter frequency to a frequency supplied to the limited amplifier (wideband) and combined wideband discriminator:

i. The discriminator must be sensitive enough to measure signals down to (P_of) - 30 dB;

ii. The discriminator must be fast enough to display frequency deviations (about 100 kHz/100 μs);

iii. The discriminator output must be direct-coupled DC.

2.2.7.4.3. Measurement of Adjacent Channel Transient Power

The transmitter under test shall be placed within the measurement set (Section A.4) and connected to the "adjacent channel over-coupling power measuring device" through a power attenuator as described in Section 2.2.7.3 such that the level at the input of the measuring device is between 0 dBm and -10 dBm when the transmitter power is P._of.

i. The transmitter must be unmodulated and operating at maximum power level under normal measurement conditions.

ii. Adjust the "over-coupling power meter" to obtain the maximum response. This is the reference level of 0 dBc.

iii. Adjust the tuning of the "over-coupling power meter" off the carrier frequency so that the response is -6 dB relative to the carrier frequency of the transmitter shifted from the nominal carrier frequency as shown in Table 8.

Table 8 - Frequency Shift

iv. Turn on the transmitter.

v. Use a spectrum analyzer to record the first 35 ms of the over-coupling power envelope curve over time. Record the peak over-coupling power envelope in dBc.

vi. Turn off the transmitter.

vii. Use a spectrum analyzer to record the first 35 ms of the over-coupling power envelope curve over time. Record the peak over-coupling power envelope in dBc.

viii. Repeat steps iii. to vii. with the "over-coupling power meter" adjusted to the other side of the carrier wave.

ix. The adjacent channel over-coupling power during activation and deactivation times is the dBc value corresponding to the highest power level among the four values obtained for the adjacent channels recorded in steps v. and vii.

2.2.7.4.4. Characteristics of the adjacent channel over-coupling power measuring device

Requirements for the adjacent channel over-coupling power measuring device are as follows:

i. Mixer: A balanced diode mixer with a 50 Ω impedance; with suitable internal oscillation level, for example +7 dBm;

ii. Adjacent channel filter: Suitable for a 50 Ω impedance (Appendix B);

iii. Spectrum analyzer: With a bandwidth of 100 kHz, capable of peak detection or power/time measurement.

Figure 13 - Schematic diagram of the adjacent channel over-coupling power measuring device

2.3. Requirements for Receivers

2.3.1. Average receiver sensitivity (field strength, data or message)

2.3.1.1. Definition

Average usable sensitivity (data) is represented by the average field strength in units of dBμV/m generated by the carrier signal at the designated frequency of the receiver modulated with a normal measurement signal (Section 2.1.3.1). This signal, excluding noise, after demodulation produces a data signal with a defined bit error rate of 10^-2­ or a defined packet success rate of 80 %.

The average value is calculated from eight measurements of field strength at the receiver rotated gradually by 45^° degrees starting from any direction.

NOTE: The average usable sensitivity differs very little from the maximum usable sensitivity when measured in a specific direction. This is due to the averaging process as per the formula in Section 2.3.1.3. For example, the error cannot exceed 1.2 dB if the sensitivity in seven directions is equivalent, while in the eighth direction it is very poor. For this reason, the starting direction (or angle) can be chosen randomly.

2.3.1.2. Limits

- Type A3 includes: Senior Specialist, Senior Auditor, and equivalent positions;: Device with integral antenna completely enclosed within the housing.

Type B: Device with integral antenna fixed or extendable up to a maximum of 20 cm.

Type C: Device with integral antenna fixed or extendable more than 20 cm.

Type D: Device not included in types A, B, or C above.

Under normal measurement conditions, the average usable sensitivity for devices of types A, B, and D shall not exceed the field strength values given in Tables 9 and 10.

Table 9 - Sensitivity limits for devices of type A and D

Table 10 - Sensitivity limits for devices of type B

Under normal conditions, the limits for type C devices shall comply as follows:

- At frequencies greater than 375 MHz, the limits must comply with Table 10.

- At frequencies less than or equal to 375 MHz, the field strength values in Table 10 shall be reduced by correction factor K, which is calculated as follows:

K = 20 log₁₀[(l + 20)/40]

- Where: l is the length of the external part of the antenna in centimeters.

This adjustment is only applicable if the external antenna length outside the housing is less than (15 000/f₀ - 20) cm, where f₀ is the frequency in MHz.

For all the aforementioned devices, the limit value measured under threshold measurement conditions equals the limit value measured under normal measurement conditions plus 6 dB.

2.3.1.3. Measurement Method

2.3.1.3.1. Measurement with continuous bit streams under normal measurement conditions

Figure 14 - Schematic diagram for measuring sensitivity with continuous bit streams under normal measurement conditions

i. Connect the measurement antenna to the signal generator. Adjust the frequency on the signal generator to the designated frequency of the receiver and use the normal measurement signal D-M2 (see 2.1.3.1).

ii. The bit pattern of the modulated signal is compared with the bit pattern of the receiver after demodulation to obtain the bit error rate.

iii. Adjust the level of the signal generator until a bit error rate of 10^-1.

is achieved.

iv. Adjust the height of the measurement antenna according to the specified height to find the lowest bit error rate; If the measurement position conforms to Section A.1.2 or if ground reflection is effectively excluded, it is not necessary to change the height of the measurement antenna.^-2.

v. Re-adjust the level of the signal generator again until a bit error rate of 10

is achieved.⁰).

vi. Record the minimum level of the signal generator in step iv._{international} vii. Repeat steps from iii. to vi. for the remaining seven directions of the receiver (each rotation by 45

degrees)._Medium viii. Using the relationship in Section A.1.2, the field strengths in eight directions X

(i = 1,..., 8) in μV/m corresponding to the levels obtained from the signal generator will be calculated and recorded._{international} ix. The average usable sensitivity of the receiver is represented by the field strength E

(dBμV/m) determined by the following formula:

where X

is the quantity of the eight calculated field strengths in step viii.

x. The reference direction is the direction with the maximum sensitivity (corresponding to the lowest field strength obtained during the measurement) appearing during the measurement at eight positions.

Determine the input level of the measurement signal to create a bit error ratio of 10^-2 under normal and threshold measurement conditions, the difference is calculated in dB. Add this difference to the average sensitivity in normal measurement conditions for radiation fields, expressed in dBμV/m as per Section 2.3.1.3.1, Step i, to obtain the sensitivity in threshold measurement conditions.

2.3.1.3.3. Measurement with messages under normal measurement conditions

Figure 16 - Diagram for measuring sensitivity with messages under normal measurement conditions

i. Connect the measurement antenna to the signal generator. Adjust the frequency on the signal generator to match the nominal frequency of the receiver and use the normal modulation (as per Section 2.1.3.1).

ii. Adjust the level of the signal generator until a message success rate less than 10% is achieved.

iii. Adjust the height of the measurement antenna within the specified range to find the highest message success rate; If the measurement position meets the specified requirements or if ground reflection is effectively excluded, there is no need to change the height of the measurement antenna. Re-adjust the level of the measurement signal to achieve the specified successful message rate in Step ii.

iv. Record the minimum level of the signal generator in Step iii.

v. The normal measurement signal is continuously transmitted while observing each case to see if the message is successfully received.

Increase the measurement signal level by 2 dB for each unsuccessful reception of a message.

Continue the procedure until three consecutive successful messages are received.

Record the minimum level of the signal generator in this direction.

vi. Decrease the level obtained in Step v by 1 dB and record the new value.

Transmit the normal measurement signal 20 times. For each case, if an unsuccessful message is received, increase the signal level by 1 dB and record the new value.

If a successful message is received, no change in level is needed until three consecutive successful messages are received.

In this case, decrease the signal level by 1 dB and record the new value.

The average value corresponding to a message success rate of 80% is obtained. This value will be used to calculate the field strength related to each position in Step viii.

vii. Repeat Steps ii. to vi. for the remaining 7 directions of the receiver (each angle rotation 45 degrees).⁰).

viii. Using the relationship described in Section A.1.2, the field strengths in 8 directions (i = 1,..., 8) measured in μV/m corresponding to the average values above will be calculated and recorded;_{international} (dBμV/m) given by the formula:

degrees)._Medium Where Xi is the magnitude of the 8 field strengths calculated in Step viii.

2.3.1.3.4. Measurement with messages under threshold measurement conditions

(dBμV/m) determined by the following formula:

where X

Figure 17 - Diagram for measuring sensitivity with messages under threshold measurement conditions

Use the combination measurement setup in Figure 17 to measure the average available sensitivity with messages under threshold measurement conditions.

Determine the input level of the measurement signal to create a message success rate of 80% under normal and threshold measurement conditions, the difference is calculated in dB. Add this difference to the average sensitivity in normal measurement conditions for radiation fields, expressed in dBμV/m as per Section 2.3.1.3.3, Step ix, to obtain the sensitivity in threshold measurement conditions.

2.3.1.3.5. Attenuation Measurement

a. Definition

Attenuation measurement is a test performed on the receiver to determine the quality degradation of the receiver due to the presence of one or more unwanted signals (noise). For such measurements, the desired signal level must be adjusted higher than the average available sensitivity limit by 3 dB depending on the type of equipment and is represented by field strength.

Attenuation measurement is divided into two types:

- Measurement conducted at the measurement location;

- Measurement conducted using the combination measurement setup.

Only the combination measurement setup is used for measurements where the frequency deviation between the desired and unwanted measurement signals is very small compared to the actual frequency, thus the coupling loss of the combination measurement setup is the same for both the desired and unwanted signals.

b. Procedure for measurement using the combination measurement setup

Connect the combination measurement setup to the signal generator through a combiner to generate the desired and unwanted measurement signals into the receiver placed in the combination measurement setup. Therefore, it is necessary to set the output level of the desired measurement signal from the signal generator to produce a signal at the receiver (placed in the combination measurement setup) corresponding to the average available sensitivity (field strength) determined in Section 2.3.1.2.

The output level of this desired measurement signal from the signal generator is used for all receiver measurements using the combination measurement setup.

The method for determining the output measurement level from the signal generator is as follows:

i. Measure the actual average available sensitivity of the receiver according to Section 2.3.1.3, Step ix, expressed in field strength.

ii. Record the difference between the average available sensitivity limit defined in Section 2.3.1.2 and the actual average available sensitivity above (Step i), expressed in dB.

iii. Place the receiver in the combination measurement setup.

Connect the signal generator generating the desired signal to the combination measurement setup through a combiner. All other inputs of the combiner are terminated with a 50 Ω impedance;

For continuous bit streams, adjust the output level of the signal generator with the normal measurement signal D-M2 to achieve a bit error rate of 10

. Then increase this output level by an amount corresponding to the difference in dB as in Step ii.^-2For messages, adjust the output level of the signal generator with normal measurement modulation to achieve a message success rate of 80%. Then increase this output level by an amount corresponding to the difference in dB as in Step ii.

For each type of equipment used, the output level of the signal generator is determined equivalent to the average available sensitivity limit for that equipment, expressed in field strength (see Section 2.3.1.2).

c. Procedure for measurement at the measurement location

When the measurement is conducted at an appropriate measurement location, the desired and unwanted signals are calibrated in dBμV/m at the location of the equipment to be measured.

For measurements according to Sections 2.3.4, 2.3.6, and A.2, the height of the measurement antenna and the direction (angle) of the equipment to be measured must be recorded as per Section 2.3.1.3.1, Step x, and Section 2.3.1.3.3, Step x (standard direction).

2.3.2.1. Definitions

2.3.2. Error effect when input signal level is high

2.3.2.1. Definition

The performance at high input signal levels (noise-free) is determined by the bit error rate (continuous bit stream) or the number of lost or erroneous messages at signal levels exceeding the maximum available sensitivity.

2.3.2.2. Limitations

The bit error rate (continuous bit stream) shall not exceed 10^-4.

The number of incorrectly received messages (lost or erroneous) shall not exceed 1 message.

2.3.2.3. Measurement Method

2.3.2.3.1. Measurement method with continuous bit streams

Figure 18 - Measurement method for error performance on continuous bit streams

i. The receiver must be placed in the test setup. The input signal has a frequency equal to the nominal frequency of the receiver, modulated with the normal measurement signal D-M2 and connected to the input of the test setup.

ii. The bit pattern of the modulated signal must be compared with the bit pattern obtained from the receiver after demodulation to obtain the bit error rate.

iii. The input signal must be adjusted to a level 30 dB higher than the desired signal level in the attenuation measurements.

iv. Count the number of errors occurring at the end of the receiver's data output or at a point to be measured on the receiver over a period of 3 minutes.

v. Repeat the measurement with the input signal of the test setup at a level above 100 dB compared to the desired signal in the attenuation measurements.

2.3.2.3.2. Measurement method with messages

Figure 19 - Measurement method for error performance on messages

i. The receiver must be placed in the test setup. The carrier input signal has a frequency equal to the nominal frequency of the receiver, modulated with the normal measurement signal D-M2 and connected to the input of the test setup.

ii. The input signal must be adjusted to a level 30 dB higher than the desired signal level in the attenuation measurements.

iii. Perform transmission of the normal measurement signal 100 times and observe whether the message is successfully received.

iv. Record the number of times the message is not successfully received.

v. Repeat the measurement with the input signal of the test setup at a level above 100 dB compared to the desired signal in the attenuation measurements.

2.3.3. Co-channel interference rejection

2.3.3.1. Definition

Co-channel interference suppression is the measure of the receiver's ability to receive the desired modulated signal without exceeding the given attenuation due to the presence of an unwanted modulated signal, both signals being at the receiver's nominal frequency.

2.3.2.2. Limitations

The value of the co-channel interference suppression ratio, expressed in dB, at any frequency of the unwanted signal will lie within the range:

- From -8.0 dB to 0 dB, for a channel spacing of 25 kHz;

- From -12.0 dB to 0 dB, for a channel spacing of 12.5 kHz.

2.3.3.3. Measurement Method

2.3.3.3.1. Measurement method with continuous bit streams

i. The measuring device is placed in the test setup. Connect two signal generators A and B to the receiver under test through a combiner;

The desired signal from generator A is set at the receiver's nominal frequency and modulated with the normal measurement signal D-M2 (see 2.1.3.1.1).

The unwanted signal from generator B must be modulated with signal A-M3 (see 2.1.3.1).

Both input signals must be set at the receiver's nominal frequency under test.

Figure 20 - Diagram for measuring co-channel interference suppression on continuous bit streams

ii. Initially, turn off the unwanted signal (while maintaining the output load resistor). Adjust the level of the desired signal from generator A to be 3 dB higher than the limit of the average available sensitivity, for the type of equipment used, represented by field strength.

iii. Turn on generator B and adjust the level of the unwanted signal until the bit error rate reaches 10^-1.

iv. Transmit the normal measurement signal D-M2 while observing the bit error rate.

v. Reduce the level of the unwanted signal in steps of 1 dB until the bit error rate reaches 10^-2 or better. Record the level of the unwanted signal.

vi. For each frequency of the unwanted signal, the co-channel interference suppression ratio must be expressed as the ratio of the unwanted signal level to the desired signal level (in dB). Record this ratio.

vii. Repeat the measurement with the unwanted signal shifted ± 12% of the channel spacing.

viii. The co-channel interference suppression of the device under test is represented by the lowest value in dB among the three values recorded in step vi.

The value of the co-channel interference suppression ratio, expressed in dB, is usually a negative number.

2.3.3.3.2. Measurement method with messages

Figure 21 - Diagram for measuring co-channel interference suppression on messages

i. The measuring device is placed in the test setup. Connect two signal generators A and B to the receiver under test through a combiner;

The desired signal from generator A is set at the receiver's nominal frequency and modulated with the normal measurement signal D-M3 (see 2.1.3.1.2).

The unwanted signal from generator B must be modulated with signal A-M3 (see 2.1.3.1).

Both input signals must be set at the receiver's nominal frequency under test.

ii. Initially, turn off the unwanted signal. Adjust the level of the desired signal from generator A to be 3 dB higher than the limit of the average available sensitivity, for the type of equipment used, represented by field strength.

iii. Turn on generator B and adjust the level of the unwanted signal until the message success ratio is lower than 10%.

iv. Re-transmit the normal measurement signal while observing in each case whether the message is successfully received or not.

Reduce the level of the unwanted signal by 2 dB in each case where the message is not successfully received.

Continue the measurement until the message is successfully received three times consecutively. Then record the level of the input signal.

v. Increase the level of the unwanted signal by 1 dB and record the new value.

Then transmit the normal measurement signal 20 times. In each case, if the message is not successfully received, reduce the level of the unwanted signal by 1 dB and record the new value.

Record the average values (corresponding to a message success ratio of 80%) in steps iv. and v.

vi. For each frequency of the unwanted signal, the co-channel interference suppression ratio must be expressed as the ratio (in dB) of the average value obtained in step v. to the desired signal level. Record this ratio.

vii. Repeat the measurement with the unwanted signal shifted ± 12% of the channel spacing.

viii. The co-channel interference suppression ratio of the device under test does not exceed the lowest value among the three values obtained in step vi., expressed in dB.

2.3.4. Adjacent channel selectivity

2.3.4.1. Definition

Adjacent channel selectivity is the measure of the receiver's ability to receive the desired modulated signal without exceeding the given attenuation due to the presence of an unwanted signal at a frequency offset from the desired signal frequency by an adjacent channel spacing of the equipment.

2.3.4.2. Limitations

The adjacent channel selectivity of the device under specified measurement conditions for different channel spacings shall not exceed the unwanted signal levels set forth in Table 11.

Table 11 - Adjacent Channel Selectivity

2.3.4.3. Measurement Method

2.3.4.3.1. Measurement method with continuous bit stream

Figure 22 - Diagram for measuring adjacent channel selectivity with a continuous bit stream

i. The receiver to be measured is placed in the test setup. Connect two signal generators A and B to the receiver to be measured through a combiner.

The desired signal from generator A is set at the receiver's designated frequency and modulated with normal measurement signals D-M2.

The undesired signal from generator B must be modulated with signal A-M3 and placed at the frequency of the nearest adjacent channel, which must be higher than the frequency of the desired signal channel.

ii. Initially, turn off the undesired signal. Adjust the level of the desired signal from generator A to be 3 dB higher than the average usable sensitivity limit for the type of equipment being used, expressed as field strength.

iii. Turn on generator B and adjust the level of the undesired signal until a bit error rate of approximately 10^-3 is achieved.^-1.

iv. Transmit the normal measurement signal D-M2 while observing the bit error rate.

v. Reduce the level of the unwanted signal in steps of 1 dB until the bit error rate reaches 10^-2 or better. Record the level of the unwanted signal.

vi. For each adjacent channel, the selectivity must be represented by the ratio in dB of the undesired signal level to the desired signal level. Record this ratio.

vii. Repeat the measurement with the undesired signal at the frequency of the adjacent channel that has a lower frequency than the desired signal channel.

viii. The adjacent channel selectivity of the device to be measured is the lower of the two values obtained from the upper and lower adjacent channel limits in step vi.

2.3.4.3.2. Method for packets

Figure 23 - Diagram for measuring adjacent channel selectivity for packets

i. The receiver to be measured is placed in the test setup. Connect two signal generators A and B to the receiver to be measured through a combiner.

The desired signal from generator A is set at the receiver's designated frequency and modulated with normal measurement signals.

The undesired signal from generator B must be modulated with signal A-M3 and placed at the frequency of the nearest adjacent channel, which must be higher than the frequency of the desired signal channel.

ii. Initially, turn off the unmodulated signal. Adjust the level of the desired signal from generator A to be 3 dB higher than the average usable sensitivity limit for the type of equipment being used, expressed as field strength.

iii. Turn on generator B and adjust the level of the unwanted signal until the message success ratio is lower than 10%.

iv. Re-transmit the normal measurement signal while observing in each case whether the message is successfully received or not.

Reduce the level of the unwanted signal by 2 dB in each case where the message is not successfully received.

Continue the procedure until three consecutive successful packet receptions are achieved. Then record the signal level.

v. Increase the undesired signal level by 1 dB and record the new value.

Then transmit the normal measurement signal 20 times. In each case, if the message is not successfully received, reduce the level of the unwanted signal by 1 dB and record the new value.

If a successful packet reception is achieved, then there is no need to change the undesired signal level until three consecutive successful packet receptions are achieved.

In this case, increase the undesired signal level by 1 dB and record the new value.

Do not record the undesired signal level unless there is a previous change.

Record the average of the values (corresponding to a packet success rate of 80%) obtained in steps iv. and v.

vi. For each adjacent channel, the selectivity will be represented by the ratio between the average value obtained in step v. and the undesired signal level, expressed in dB. Record this value.

vii. Repeat the measurement with the undesired signal at the frequency of the adjacent channel that has a lower frequency than the desired signal channel.

viii. The adjacent channel selectivity of the device to be measured is the lower of the two values obtained from the upper and lower adjacent channel limits in step vi.

2.3.5. Spurious response rejection

2.3.5.1. Definition

Spurious response suppression is the ability of the receiver to receive the desired modulated signal without exceeding the prescribed quality degradation due to the presence of an undesired modulated signal at any other frequency having a response.

2.3.5.2. Limits

The spurious response of the equipment must ensure that, under specified measurement conditions, the prescribed quality degradation does not exceed when the level of the undesired signal reaches:

- Level 75 dBµV/m for undesired signals with frequencies ≤ 68 MHz;

- Level (38.3 + 20log₁₀f) dBµV/m for undesired signals with frequencies > 68 MHz, where f is the carrier frequency (MHz).

2.3.5.3. Measurement Method

2.3.5.3.1. Introduction to the measurement method

To determine the frequencies with spurious responses, the following calculations must be performed:

a. Calculate "the frequency band limit":

The frequency band limit is defined as the frequency of the local oscillator signal (f_LO) supplied to the first mixer of the receiver plus or minus the sum of all intermediate frequencies (f_I1,...f_In) and half the bandwidth of the preset channels (sr) of the receiver;

Therefore, the frequency f_L of the frequency band limit is:

b. Calculate the frequencies outside the frequency band limit:

- Calculate the frequencies with spurious responses outside the frequency band limit determined in step i. for the remaining relevant frequency bands;

- The frequencies outside the frequency band limit are the harmonics of the local oscillator signal (f_LO) supplied to the first mixer of the receiver plus or minus the first intermediate frequency (f_I1) of the receiver;

- Thus, the frequencies of these spurious responses are: nf_LO ± f_I1, where n is an integer greater than or equal to 2;

- The initial measurement of the first image response of the receiver is performed to verify the calculation of the spurious response frequencies.

With the calculations as described in steps i. and ii. above, the manufacturer must publish the receiver frequency, the frequency of the local oscillator signal (f_LO) supplied to the first mixer of the receiver, the intermediate frequencies (f_I1, f_I2,...) and the bandwidth of the preset channels (sr) of the receiver.

2.3.5.3.2. Diagram for measuring spurious response suppression

Figure 24 - Diagram for measuring spurious response suppression

i. Use the corresponding measurement position in the average usable sensitivity measurement (see 2.3.1.3).

ii. The height of the wideband antenna and the orientation (angle) of the receiver to be measured are placed according to 2.3.1.3.1 and 2.3.1.3.2.

iii. During the measurement, it may be necessary to emit high power radiation over a wide band, and care must be taken to avoid interference with services operating in nearby areas.

iv. In the case of reflection from the ground plane, the height of the wideband antenna must be changed to optimize the reflection from the ground plane. This cannot be done simultaneously for two different frequencies.

If vertical polarization is used, the reflection from the ground plane can be easily eliminated by using an appropriate single-pole antenna placed directly on the ground plane.

In the case where the broadband antenna does not cover the necessary frequency band, two different antennas may be used together to replace it.

The device under test shall be placed on the standard stand at the standard position (section A.2) and oriented according to the specified direction as indicated (see 2.3.1.3).

2.3.5.3.3. Method for searching for limit frequency bands with continuous bit streams

i. Connect signal generators A and B to the broadband measurement antenna through the combination circuit, if possible, or with two different antennas according to step 2.3.4.3.2.v.

The desired signal from signal generator A has the receiver's designated frequency and is modulated with the normal measurement signal D-M2 (see 2.1.3.1).

The undesired signal from signal generator B must be modulated with a 400 Hz frequency at the level that causes a ± 5 kHz frequency deviation.

ii. First, turn off the undesired signal (while maintaining the output impedance). Adjust the level of the desired signal from signal generator A until it is 3 dB higher than the average usable sensitivity threshold for the type of equipment being used, expressed as field strength (see 2.3.1.2).

iii. Then turn on signal generator B and adjust the level of the undesired signal so that the field strength is at least 10 dB higher.

iv. Transmit the normal measurement signal D-M2 while observing the bit error rate.

v. If the bit error rate is better than 10^-2, there is no false response effect and the search continues at the next frequency.

vi. If the bit error rate is worse than 10^-2, a false response effect is detected and the search continues at the next frequency.

vii. The frequency of any false response detected during the search and the positions of the antennas and height are recorded for use in measurements according to 2.3.4.3.

2.3.5.3.4. Method for searching within limit frequency bands using messages

i. Connect the two signal generators (A and B) to the receiver through the combiner; the desired signal from signal generator A must be at the receiver's designated frequency and modulated with the normal measurement signal D-M2. The undesired signal from signal generator B must be modulated with a 400 Hz frequency and with a ± 5 kHz deviation.

ii. First, turn off the undesired signal. Adjust the level of the desired signal from signal generator A until it is 3 dB higher than the average usable sensitivity threshold for the type of equipment being used, expressed as field strength (see 2.3.1).

iii. Then turn on signal generator B and adjust the level of the undesired signal to ensure that the field strength is at least 10 dB higher.

iv. Transmit the normal measurement signal (see 2.1.3.1.2) while observing whether a message is successfully received in each case.

v. If the message ratio is greater than 80%, there is no false response effect and the search continues at the next frequency.

vi. If three consecutive successful messages are not received, a false response effect is detected and the search continues at the next frequency.

vii. The frequency of any false response detected during the search and the positions of the antennas and height are recorded for use in measurements according to 2.3.4.3.

2.3.5.3.5. Measurement method with continuous bit streams

i. The measurement setup is similar to 2.3.4.3.1. The desired signal from signal generator A must be at the receiver's designated frequency and modulated with the normal measurement signals DM2 (see 2.1.3.1.1).

The undesired signal from signal generator B must be modulated with a 400 Hz frequency and with a 12% channel spacing deviation and must be at the frequency of the false response of interest.

ii. First, turn off the undesired signal at signal generator B.

Adjust the desired signal level from signal generator A until it exceeds the average usable sensitivity limit by 3 dB, expressed as field strength (see 2.3.1), for the type of equipment being used.

iii. Then turn on signal generator B and adjust the unwanted signal level until a bit error rate of 10 is achieved.^-1.

iv. Repeat the normal measurement signal D-M2 when observing the bit error ratio.

v. Gradually reduce the unwanted signal level by 1 dB at a time until a BER of 10 or better is obtained. Record the level of the unwanted signal.^-2 or better. Record the level of the unwanted signal.

vi. Increase or decrease the channel spacing by 20% relative to the frequency of the unwanted signal and repeat steps iii. to v. until the lowest level as in step v. is obtained.

vii. Repeat the measurements at all frequencies of spurious responses detected during the search in the "frequency band limits" (see 2.3.4.3.a and 2.3.4.3.b) and at calculated spurious frequencies within the band from f/3,2 or 30 MHz (whichever is larger) to 3,2 × f, where f is the nominal frequency of the receiver, with the antenna position and height recorded at 2.3.4.3.c, step vii._{Dải chuyển mạch}/3,2 or 30 MHz (choose the larger number) to 3,2 × f_{Dải chuyển mạch} (f_{Dải chuyển mạch} is the nominal frequency of the receiver), with the position and height of the antenna recorded at 2.3.4.3.c, step vii.

viii. The spurious response suppression of the device under test is the lowest value recorded in step vi., expressed in dBμV/m of the unwanted signal field strength at the receiver location.

2.3.5.3.6. Measurement method with messages

i. The desired signal from signal generator A (see 2.3.4.3) must be at the nominal frequency of the receiver and modulated with normal measurement signals (see 2.1.3.1.2).

The undesired signal from signal generator B must be modulated with a 400 Hz frequency and with a 12% channel spacing deviation and must be at the frequency of the false response of interest.

ii. First, turn off the undesired signal at signal generator B.

Adjust the desired signal level from signal generator A until it exceeds the average usable sensitivity limit by 3 dB, expressed as field strength, for the type of equipment being used (see 2.3.1).

iii. Then turn on signal generator B and adjust the unwanted signal level until a message success rate of less than 10% is achieved.

iv. Repeat the normal measurement signal (see 2.1.3.1.2) in each case, including when the message is successfully received or not.

Reduce the unwanted signal level by 2 dB in each case where the correct message is not received. Continue until three consecutive successful messages are received. Then record the level of the signal in.

v. Increase the undesired signal level by 1 dB and record the new value.

Then transmit the normal measurement signal 20 times. In each case, if the correct message is not received, reduce the unwanted signal level by 1 dB and record the new value.

If the correct message is received, do not change the unwanted signal level until three consecutive successful messages are received. In this case, increase the unwanted signal level by 1 dB and record the new value.

Do not record the signal level unless there has been a previous change.

Record the average values from steps iv. and v. (corresponding to a message success rate of 80%).

vi. Increase or decrease the channel spacing by 20% relative to the frequency of the unwanted signal and repeat steps iv. to v. until the lowest average level as in step v. is obtained.

vii. Repeat the measurements at all frequencies of spurious responses detected during the search in the "frequency band limits" and at calculated spurious frequencies within the band from f_{Dải chuyển mạch}/3,2 or 30 MHz (choose the larger number) to 3,2 × f_{Dải chuyển mạch} (f_{Dải chuyển mạch} is the nominal frequency of the receiver), record the position and height of the antenna.

viii. The spurious response suppression of the tested device is the lowest value recorded in step vi., expressed as the unwanted signal field strength at the receiver location.

2.3.6. Intermodulation spurious response rejection

2.3.6.1. Definitions

Spurious response suppression is a measure of the receiver's ability to receive a modulated desired signal without exceeding the specified quality degradation due to the presence of two or more unwanted signals having a specific frequency relationship with the desired signal frequency.

2.3.6.2. Limits

The spurious response suppression of the equipment must ensure that, under specified measurement conditions, the specified quality degradation does not exceed for levels of unwanted signals up to:

- Level 70 dBμV/m for unwanted signal frequencies ≤ 68 MHz.

- Level (33,3 + 20log₁₀f) dBμV/m for unwanted signal frequencies > 68 MHz, f is the carrier frequency (MHz).

2.3.6.3. Measurement methods

2.3.6.3.1. Measurement method with continuous bit stream

Figure 25 - Diagram for measuring spurious response suppression with a continuous bit stream

i. The receiver under test is placed in the measurement set-up. Connect three signal generators A, B, and C to the measurement set-up through a combiner;

The desired signal from signal generator A must be set at the nominal frequency of the receiver and modulated with normal measurement signal D-M2 (see 2.1.3.1.1).

The first unwanted signal from signal generator B must not be modulated. Adjust this signal to a frequency 50 kHz higher than the nominal frequency of the receiver.

The second unwanted signal from signal generator C must be modulated with signal A-M3 and adjusted to a frequency 100 kHz higher than the nominal frequency of the receiver.

ii. First, turn off the unwanted signals.

Adjust the desired signal level from signal generator A until it exceeds the average available sensitivity limit by 3 dB, represented by field strength for the type of equipment used (see 2.3.1).

iii. Then turn on signal generators B and C. The levels of the two undesired signals must be kept equal and adjusted until a bit error rate of 10 or worse is achieved.^-1 or worse.

iv. Transmit the normal measurement signal D-M2 while observing the bit error rate.

v. Decrease the undesired signal level in steps of 1 dB until a bit error rate of 10 is achieved.^-2 or better. Record the level of the unwanted signal.

vi. For each configuration of the undesired signals, the cross-modulation suppression must be expressed as the ratio of the undesired signal levels to the desired signal level, in dB. Record this ratio.

vii. Repeat the measurement with the undesired signal generator B at a frequency 50 kHz lower than the desired signal frequency and the undesired signal generator C at a frequency 100 kHz lower than the desired signal frequency.

viii. The cross-modulation suppression of the tested device is the lower value of the two values recorded in step vi.

2.3.6.3.2. Measurement method with packets

Figure 26 - Block diagram for measuring cross-modulation suppression with packets

i. The receiver to be measured must be placed in the test setup.

Connect three signal generators A, B, and C to the test setup through a combiner;

The desired signal from signal generator A must be set at the receiver's nominal frequency and modulated with the normal test signal D-M2 (see 2.1.3.1.2).

The first unwanted signal from signal generator B must not be modulated. Adjust this signal to a frequency 50 kHz higher than the nominal frequency of the receiver.

The second undesired signal from signal generator C must be modulated with signal A-M3 (see 2.1.3.1) and adjusted to a frequency 100 kHz higher than the receiver's nominal frequency.

ii. First, turn off the undesired signals at signal generators B and C.

Adjust the desired signal level from signal generator A until it exceeds the average available sensitivity limit by 3 dB.

iii. Then turn on signal generators B and C. Keep the levels of the two undesired signals equal and adjust them until the packet success ratio is less than 10%.

iv. Transmit the normal test signal (see 2.1.3.1.2) while observing whether the packets are received successfully or not.

Reduce the undesired signal level by 2 dB each time the packet is not accurately received.

Continue the procedure until the packet is successfully received three times consecutively. Record the signal levels.

v. Increase the undesired signal levels by 1 dB and record the new value.

Then transmit the normal test signal (see 2.1.3.1.2) 20 times. If the correct packet is not received in any case, reduce the undesired signal levels by 1 dB and record the new value.

If the packet is received successfully, no change is needed until three consecutive successful receptions occur, in which case the undesired signal level will be increased by 1 dB, and the new value will be recorded.

Do not record the signal level unless there has been a previous change.

Record the average value in steps iv. and v. (corresponding to a packet success ratio of 80%).

vi. For each configuration of the undesired signals, the cross-modulation suppression must be expressed as the ratio of the average value recorded in step v. to the desired signal level, in dB. Record this ratio.

2.3.7. Blocking characteristic

2.3.7.1. Definition

Blocking characteristic is a measure of the receiver's ability to receive the desired modulated signal without exceeding the specified degradation due to the presence of an undesired signal at any frequency other than the adjacent channel response frequency or the frequencies of neighboring channels.

2.3.7.2. Limitations

The blocking level at any frequency within the specified range must:

- Be limited to ≥ 89 dB μV/m for undesired signal frequencies ≤ 68 MHz.

- Be limited to ≥ (52.3 + 20log f) dBμV/m for undesired signal frequencies greater than 68 MHz, where f is the carrier frequency value in MHz.₁₀f) dBμV/m for unwanted signals frequencies greater than 68 MHz, where f is the carrier frequency value in MHz.

2.3.7.3. Measurement Method

2.3.7.3.1. Measurement Method with Continuous Bit Streams

Figure 27 - Block diagram for measuring blocking characteristics with continuous bit streams

i. Connect two signal generators (A and B) to the wideband antenna through a combiner;

The desired signal from signal generator A must be at the receiver's nominal frequency and modulated with the normal test signal D-M2.

The undesired signal from signal generator B must be unmodulated and at a frequency between 1 MHz and 10 MHz away from the receiver's nominal frequency.

In practice, measurements must be performed at undesired signal frequencies approximately ± 1 MHz, ± 2 MHz, ± 5 MHz, and ± 10 MHz, avoiding frequencies with adjacent channel responses (see 2.3.4).

ii. First, turn off the undesired signal. Adjust the desired signal level from signal generator A until it exceeds the average available sensitivity limit by 3 dB.

iii. Then turn on signal generator B and adjust the unwanted signal level until a bit error rate of 10 is achieved.^-1.

iv. Transmit the normal measurement signal D-M2 while observing the bit error rate.

v. Decrease the undesired signal level in steps of 1 dB until a bit error rate of 10 is achieved.^-2 or better. Record the level of the unwanted signal.

vi. For each frequency, the blocking characteristic must be expressed as the dBμV/m level of the undesired field strength signal at the receiver location. Record this value.

vii. Repeat the measurement at all frequencies determined in step i.

viii. The blocking characteristic of the tested device is the lowest dBμV/m level of the undesired signal strength recorded at the receiver location in step vi.

2.3.7.3.2. Measurement Method with Packets

Figure 28 - Block diagram for measuring blocking characteristics with packets

i. Connect two signal generators A and B to the wideband antenna through a combiner;

The desired signal from signal generator A must be at the receiver's nominal frequency and modulated with the normal test signal D-M2 (see 2.1.3.1.2).

The undesired signal from signal generator B must be unmodulated and located at a frequency between 1 MHz and 10 MHz away from the receiver's nominal frequency.

In practice, measurements must be performed at undesired signal frequencies approximately ± 1 MHz, ± 2 MHz, ± 5 MHz, and ± 10 MHz, avoiding frequencies with adjacent channel responses.

ii. First, turn off the undesired signal.

Adjust the desired signal level from signal generator A until it exceeds the average sensitivity limit by more than 3 dB;

iii. Then turn on signal generator B and adjust the unwanted signal level until the success rate of the message transmission is less than 10%;

iv. Repeat the normal measurement signal when observing whether the message is successfully received in each case;

Reduce the unwanted signal level by 2 dB in each case where the message is not successfully received;

Continue this process until the message is successfully received three consecutive times. Record the signal level at that point;

v. Increase the undesired signal level by 1 dB and record the new value.

Then transmit the normal measurement signal (see 2.1.3.1.2) twenty times. In each case, if the message is not successfully received, reduce the unwanted signal level by 1 dB and record the new value;

If the message is successfully received, do not change the unwanted signal level until three consecutive successful messages are received. In this case, increase the unwanted signal level by 1 dB and record the new value;

Do not record the signal level unless there has been a previous change.

Record the average value in steps iv. and v. (corresponding to a packet success ratio of 80%).

vi. For each frequency, the blocking characteristic must be represented by the dBμV/m level of the unwanted field signal at the receiver position corresponding to the average value obtained in item e). Record this value for each frequency;

vii. Repeat the measurement at all frequencies determined in step i.

viii. The blocking characteristic of the device under test is the lowest value among those recorded in step vi., expressed as the unwanted signal field strength at the receiver position;

2.3.8. Spurious emissions

2.3.8.1. Definition

Spurious emissions from the transmitter are components at any frequency radiated by the equipment and antenna. They are defined as the power radiated by any discrete signal;

2.3.8.2. Limits

The power of spurious emissions shall not exceed the values given in Table 12;

Table 12 - Spurious Emission Components

2.3.8.3. Measurement Method

Figure 29 - Diagram for measuring spurious emissions

i. The measurement antenna is oriented vertically polarized and connected to a spectrum analyzer or selected frequency voltmeter. The resolution bandwidth of the spectrum analyzer or selected frequency voltmeter must be the smallest possible bandwidth and greater than the bandwidth of the spurious component being measured;

ii. Place the device under test on a stand at the standard position (section A.2). Any spurious emissions will be detected by the measurement antenna and the spectrum analyzer or selected frequency voltmeter over the frequency band of 30 MHz to 4 GHz. If the devices operate above 470 MHz, the measurements are repeated over the frequency band of 4 GHz to 12.75 GHz;

iii. At each frequency where a spurious component is detected, vary the height of the measurement antenna and adjust the spectrum analyzer until the maximum signal level is obtained on the spectrum analyzer or selected frequency voltmeter;

iv. Rotate the device under test around its vertical axis 360 degrees to find the maximum received signal level;^° to find the maximum received signal level;

v. Raise or lower the measurement antenna within the specified height range to obtain the maximum signal. Record this value;

vi. Using the measurement diagram in Figure 26, replace the transmitter antenna with a substitute antenna in the same position and vertical polarization. Connect the antenna to the signal generator;

vii. At each frequency where a spurious component is detected, adjust the spectrum analyzer or selected frequency voltmeter and the signal generator, and vary the height of the measurement antenna within the specified height range until the maximum signal level is obtained on the spectrum analyzer or selected frequency voltmeter;

Figure 30 - Diagram for measuring spurious emissions using a substitute antenna;

The measurement antenna does not need to be raised or lowered if the measurement is performed at the measurement position according to section A.1.2;

Record the signal level generated by the signal generator corresponding to the signal level on the spectrum analyzer or selected frequency voltmeter as in step v. After adjusting for the gain of the substitute antenna and the loss of the cable between the signal generator and the substitute antenna, this value is the spurious emission component at this frequency;

viii. Repeat the measurements from step ii. to step vii. for the measurement antenna with horizontal polarization;

·3. MANAGEMENT REGULATIONS

3.1. Radio devices within the scope regulated in Article 1.1 must comply with the technical standards set forth in these Standards;

3.2. Testing/measurement requirements for these standards (except sections 2.2.2.3.3, 2.3.1.3.2, and 2.3.1.3.4) for certification and declaration of conformity must be carried out in accordance with current regulations. Organizations and individuals may use testing/measurement results from designated domestic laboratories or recognized foreign laboratories or manufacturer testing/measurement results for sections 2.2.2.3.3, 2.3.1.3.2, and 2.3.1.3.4 for certification and declaration of conformity;

·4. RESPONSIBILITIES OF ORGANIZATIONS AND INDIVIDUALS

Relevant organizations and individuals are responsible for implementing regulations on certification and declaration of conformity for terrestrial mobile radio devices with integrated antennas used for data transmission and voice communication and are subject to inspection by state management agencies in accordance with current regulations;

·5. IMPLEMENTATION ORGANIZATION

5.1. The Telecommunications Administration, the Radio Frequency Management Department, and Provincial Information and Communications Departments are responsible for guiding the implementation of management of terrestrial mobile radio devices with integrated antennas used for data transmission and voice communication in accordance with these Standards;

5.2. These Standards replace QCVN 44:2011/BTTTT "National Technical Regulations for Terrestrial Mobile Radio Devices with Integrated Antennas Used for Data Transmission (and Voice)";

5.3. In case there are changes, supplements, or replacements to the provisions set out in this Standard, they shall be implemented according to the new document.

5.4. During the implementation of these Standards, if any issues arise, relevant organizations and individuals should report them in writing to the Ministry of Information and Communications (Science and Technology Department) for guidance and resolution./.

 

·Appendix A

·(Provisions)

Field Strength Measurement

A.1. Measurement Positions and General Layout for Measurements Using Field Strength

This Appendix sets out the three most commonly used measurement positions for radiation measurements: non-reflective chamber, non-reflective chamber with ground plane, and outdoor test site (OATS). These measurement positions are often referred to as free-field measurement positions. Both absolute and relative measurements can be performed at these positions. When performing absolute measurements, the measurement chamber must be checked. Detailed evaluation procedures are described in Sections 2, 3, and 4 of TR 102 273.

NOTE: To ensure reproducibility and adherence of radiation measurements, only the measurement positions below should be used for radiation measurements according to this Technical Specification.

A.1.1. Non-Reflective Chamber

The non-reflective chamber is a closed room typically enclosed, with interior walls, floor, and ceiling covered with radio wave absorbing material usually in the form of urethane foam pyramids. The chamber usually has an antenna support column at one end and a turntable at the other. An example of a non-reflective chamber is shown in Figure A.1.

Figure A.1 - Non-Reflective Chamber

The combination of radio wave absorbing materials and the chamber enclosure creates a controlled environment suitable for measurement purposes. This type of chamber simulates free-space conditions.

The chamber enclosure provides a measurement space, reducing interference levels from surrounding signals as well as other external effects, while the radio wave absorbing material minimizes unwanted reflections from walls and ceilings that could affect measurements. In practice, it is easy to enclose to achieve high levels of surrounding interference rejection (from 80 dB to 140 dB), typically resulting in negligible surrounding interference levels.

The turntable allows rotation of 360 degrees in the horizontal plane and is used to place the test sample (EUT) at an appropriate height (for example, 1 m) above the ground. The measurement chamber must be large enough to allow a measurement distance of at least 3 m or 2(d/λ (m), choosing the larger value (see A.2.5). The measurement distance used in practical measurements must be recorded along with the measurement results.^° Non-reflective chambers generally have several advantages over other measurement conditions. They reduce environmental interference, minimize reflections from the floor, ceiling, and walls, and are not dependent on weather conditions. However, there are some disadvantages, such as limited measurement distances and restricted use at low frequencies due to the size of the pyramid-shaped absorber materials. To improve low-frequency performance, a structure combining ferrite tiles and urethane foam absorbers can be used.₁+ d₂)²All emission, sensitivity, and immunity measurements can be conducted in a non-reflective chamber without restriction.

A.1.2.

Non-Reflective Chamber with Ground Plane

The non-reflective chamber with ground plane is a closed room enclosed, with interior walls and ceiling covered with radio wave absorbing material typically in the form of urethane foam pyramids. The floor of the chamber is metallic, uncovered, and forms a ground plane. The chamber usually has an antenna support column at one end and a turntable at the other. An example of a non-reflective chamber with ground plane is shown in Figure A.2. This type of chamber simulates an ideal outdoor measurement position characterized by a perfect infinite ground plane.

Figure A.2 - Non-Reflective Chamber with Ground Plane

In this measurement position, the floor creates a desired reflection path, so the signal received by the receiving antenna is the sum of the direct and reflected signals from the transmitting antenna (or EUT). This results in a unique received signal level for each height of the transmitting antenna (or EUT) and receiving antenna above the floor.

The variable-height antenna column (from 1 m to 4 m) optimizes the position of the test antenna to maximize the coupling between antennas or between an EUT and the test antenna.

in the horizontal plane, and is used to place the test sample (EUT) at a specified height, typically 1.5 m, above the floor. The measurement chamber must be large enough to allow a measurement distance of at least 3 m or 2(d/λ (m), choosing the larger value (see A.2.5).

Emission measurements first involve determining the "peak" field strength of the EUT by raising and lowering the receiving antenna on the antenna column (to obtain the maximum combined interference of the direct and reflected signals from the EUT), then rotating the turntable to find the "peak" (maximum) value in the azimuth plane. At this height of the test antenna, record the amplitude of the received signal. Next, replace the EUT with a substitute antenna (placed at the phase center or amplitude of the EUT), which is connected to a signal generator. Find the "peak" value of the signal, and adjust the output level of the signal generator until the received signal level matches that obtained in step 1.

The turntable allows rotation of 360 degrees in the horizontal plane and is used to place the test sample (EUT) at an appropriate height (for example, 1 m) above the ground. The measurement chamber must be large enough to allow a measurement distance of at least 3 m or 2(d/λ (m), choosing the larger value (see A.2.5). The measurement distance used in practical measurements must be recorded along with the measurement results.^° Receiver sensitivity measurements on the ground plane also involve finding the "peak" field strength by raising or lowering the test antenna on the antenna column to obtain the maximum combined interference of the direct and reflected signals, using a test antenna placed at the phase center or amplitude of the EUT throughout the measurement period. Apply a conversion factor for the test antenna still at the height from step 2, simultaneously replacing the test antenna with the EUT. Reduce the signal amplitude to determine the field strength level at which a specified response is obtained from the EUT.₁+ d₂)²All emission, sensitivity, and immunity measurements can be conducted in a non-reflective chamber without restriction.

A.1.3.

Outdoor Test Site

The outdoor test site consists of a turntable at one end and a variable-height antenna column at the other on a ground plane, ideally a good conductor that can be extended indefinitely. In practice, when good conductivity is achievable, the size of the ground plane will be limited. An example of an open area test site is shown in Figure A.3. The ground plane creates a desired reflection path, so the signal received by the receiving antenna is the sum of the direct and reflected signals. The combination of these two signals produces a unique received signal level corresponding to each height of the transmitting antenna (or EUT) and receiving antenna above the ground plane.

Outdoor measurement positions include a turntable at one end and a variable height antenna mast at the other end on a ground plane, which ideally is a good conductor and can be expanded without limitation. In practice, when good conductivity is achievable, the size of the ground plane will be limited. An example of an open area test site position is shown in Figure A.3.

The ground plane creates a desired reflection path, thus the signal received by the receiving antenna is the sum of the signals from direct paths and reflections. The combination of these two signals results in a single received signal level corresponding to each height of the transmitting antenna (or EUT) and receiving antenna above the ground plane.

The characteristics of the position related to the antenna positions, turntable distances, and other measurement arrangements are similar to those for a non-reflective room with a ground plane. In radiation measurements, OATS is also used in a manner similar to a non-reflective room with a ground plane.

Figure A.3 - Outdoor Measurement Position

Typical and common measurement setups for positions with a ground plane are presented in Figure A.4.

Figure A.4 - Measurement Setup at Positions with a Ground Plane

(Setup OATS for Spurious Emission Measurement)

A.1.4. Test Antenna

Test antennas are typically used in radiation measurement methods. In emission measurements (such as frequency error, effective radiated power, spurious emissions, and adjacent channel power), the test antenna is used to detect the field from the EUT during the first stage of the measurement and from the substitute antenna in other stages. When using the test position to measure receiver characteristics (such as sensitivity and immunity parameters), the test antenna is used as a transmitter device.

The test antenna must be mounted on a support that allows it to be used in either horizontal or vertical polarization, and at measurement positions with a floor (such as in non-reflective rooms with a ground plane and open area test sites), the height of the antenna can be adjusted within a specified range (usually from 1 m to 4 m).

In the frequency band from 30 MHz to 1 000 MHz, it is recommended to use dual-polarized antennas (produced according to ANSI C 63.5 standard). For frequencies equal to or greater than 80 MHz, dual-polarized antennas should have a length that resonates at the measurement frequency. Below 80 MHz, shorter dual-polarized antennas should be used. However, for spurious emission measurements, a combination of periodic dipole dual-polarized antennas is used to cover the entire frequency band from 30 to 1 000 MHz. For frequencies above 1 000 MHz, it is recommended to use horn antennas, although periodic dipole antennas may still be used.

NOTE: The gain of the dipole antenna (electromagnetic antenna) is expressed relative to an isotropic radiator.

A.1.5. Substitute Antenna

Substitute antennas are used to replace the EUT in transmitter parameter measurements (such as frequency error, effective radiated power, spurious emissions, and adjacent channel power). For measurements in the frequency band from 30 MHz to 1 000 MHz, the substitute antenna must be a dual-polarized antenna (produced according to ANSI C63.5 standard). For frequencies equal to or greater than 80 MHz, dual-polarized antennas should have a length that resonates at the measurement frequency. Below 80 MHz, shorter dual-polarized antennas should be used. For measurements above 1 000 MHz, a horn antenna should be used. The center of this antenna must coincide with the phase center or amplitude center.

A.1.6. Measurement Antenna

Measurement antennas are used in receiver parameter measurements of the EUT (such as immunity and sensitivity measurements). The purpose is to perform electric field strength measurements near the EUT. For measurements in the frequency band from 30 MHz to 1 000 MHz, the measurement antenna should be a dual-polarized antenna (produced according to ANSI C63.5 standard). For frequencies equal to or greater than 80 MHz, dual-polarized antennas should have a length that resonates at the measurement frequency. Below 80 MHz, shorter dual-polarized antennas should be used. The center of this antenna must coincide with the phase center or amplitude center of the EUT (as specified in the measurement method).

A.2. Guidelines for Using Radiation Measurement Positions

This section sets out in detail the procedures, equipment setup, and evaluation steps that should be carried out before any radiation measurements are performed. This mechanism applies to all measurement positions described in Appendix A.

A.2.1. Evaluation of Measurement Position

No measurement should be conducted at a measurement position that does not have a valid calibration certificate. The calibration procedures for different types of measurement positions described in Appendix A (for example, non-reflective chambers, non-reflective chambers with ground planes, and outdoor measurement positions) are presented in Sections 2, 3, and 4 of TR 102 273.

A.2.2. Preparation of EUT

The manufacturer must provide information about the EUT including operating frequency, polarization, supply voltage, and reference surface. Additional specific information for each type of EUT should include carrier power, channel spacing, other operating modes (such as low and high power modes), and whether operation is continuous or subject to a maximum working cycle (for example, 1 minute on, 4 minutes off).

Where necessary, there should be a minimum-sized mounting plate to mount the EUT on a turntable. This plate must be made from material with a relatively low dielectric constant (for example, less than 1.5) and low conductivity such as polystyrene, balsa wood (softwood), etc.

A.2.3. Powering the EUT

All measurements must be performed using power sources wherever possible, including measurements with EUT designed to operate solely on batteries. In all cases, electrical leads must be connected to the EUT's power supply inputs (and monitored by a digital voltmeter) but batteries should remain in the device and insulated from the rest of the equipment, possibly by taping over the contacts.

However, the presence of these power cables may affect the quality of the EUT measurement. For this reason, conditions must be created for "transparent" measurement processes. This can be achieved by directing them away from the EUT and leading down under the screen, ground plane, or wall of the measurement position (as appropriate) along the shortest possible paths. Care should be taken to minimize losses on these leads (for example, twisting the leads together, loading them with ferrite beads every 0.15 meters, or other loads).

A.2.4. Setting Volume Control for Analog Speech Measurements

Unless otherwise specified, in all analog speech measurements of receivers, the receiver amplitude must be adjusted so that the output power is at least 50% of the rated output power. If the amplitude control is stepped, the amplitude control should be set so that the first step provides an output power of at least 50% of the rated output power. The receiver amplitude should not be readjusted between normal and limit measurement conditions during the measurements.

A.2.5. Distance

The distance for all types of measurement positions should be large enough to allow far-field measurements of the EUT, i.e., it should be equal to or greater than:

Where:

For coal-fired thermal power plants where the enterprise holds 100% of the registered capital and uses 100% of its own capital to invest in the project approved by the competent authority, E is determined as 100%;₁ the largest diameter of the EUT/dipole after replacement (m);

For coal-fired thermal power plants where the enterprise holds 100% of the registered capital and uses 100% of its own capital to invest in the project approved by the competent authority, E is determined as 100%;₂ the largest diameter of the test antenna (m);

l is the wavelength of the measurement frequency (m).

Note in the replacement part of this measurement, if both the test antenna and the replacement dipole are half-wave dipoles, the minimum distance for far-field measurement will be: 2l.

Note in the measurement result reports when one of these conditions is not met, additional uncertainty may be combined with the measurement results.

NOTE 1: For fully non-reflective chambers, at any angle of rotation of the turntable, no part of the EUT's amplitude should lie outside the "quiet zone" of the chamber at the rated measurement frequency.

NOTE 2: "Quiet Zone" is a volume within a non-reflective chamber (without a floor) where the specified quality has been proven through measurement or guaranteed by the designer/manufacturer. This specified quality is usually the reflection coefficient of the absorber panels or a directly related parameter (such as signal uniformity in amplitude and phase). However, it should also be noted that the specified levels for the quiet zone may vary.

NOTE 3: For non-reflective chambers with a floor, there should be the ability to scan the entire height, i.e., from 1 meter to 4 meters, so that no part of the test antenna lies below the 1-meter height of the absorber panels. For both types of non-reflective chambers, the reflection coefficient of the absorber panels should not be less than -5 dB.

NOTE 4: For non-reflective chambers with a floor and open space measurement positions, no part of the antenna should be within 0.25 meters of the floor at any time during the testing process. When any of these conditions are not met, measurements should not be conducted.

A.2.6. Preparation of Measurement Position

Cables at both ends of the test position must be laid horizontally at least 2 meters away from the measurement area (unless they already touch the rear wall in the case of both types of non-reflective chambers), then run vertically and outside the floor or housing (as appropriate) for the measuring equipment. Care should be taken to minimize losses on these leads (for example, by coating solder joints with ferrite or other loads). For cables, laying and coating them should match the evaluation documentation.

NOTE: For test positions with floor reflections (such as non-reflective chambers with floors and open space measurement positions), the requirement for a 2-meter distance above may not be met.

Calibration data must be available for all items of measuring equipment. For measurements and replacement antennas, this data should include the amplification factor related to the isotropic radiation field (or antenna factor) corresponding to the measurement frequency. The VSWR values of the replacement and measurement antennas should also be known.

Calibration data for all cables and attenuators should include external connection loss (insertion loss) and VSWR across the full measurement band. All diagrams of external connection loss and VSWR must be recorded in the measurement results report.

Where calibration tables/factors are required, they should be readily available.

For all items of measuring equipment, the maximum errors and error distribution should be known, for example:

- Cable loss: ± 0,5 dB with rectangular distribution;

- Receiver measurement: signal level accuracy (standard deviation) 1,0 dB with Gaussian error distribution.

At the start of measurements, system checks must be performed for the measuring equipment items used at the test location.

A.3. Signal Combining

A.3.1. Overview

The presence of electrical conductors in the radiation field can cause interference to the radiation field and result in additional measurement uncertainty. These interferences can be reduced by using appropriate combining methods that isolate signals and have minimal impact on the field (such as optical and acoustic combining).

A.3.2. Data Signals

Signal isolation can be achieved by using optical, ultrasonic, or infrared measures. The impact on the field can be minimized by using suitable optical fiber connections. Suitable infrared or ultrasonic radiation connections should be used to minimize surrounding interference.

A.3.3. Analog and Voice Signals

An acoustic coupler should be used where there are no audio outputs available.

When using an acoustic coupler, it is necessary to check whether surrounding interference affects the measurement results.

A.3.3.1. Description of Acoustic Coupler

The acoustic coupler consists of a plastic horn, an acoustic tube, and a microphone with an appropriate amplifier. Materials used to make the horn and tube should have low conductivity and a relative dielectric constant of less than 1.5 dB.

- The acoustic tube should be long enough to connect from the EUT to the microphone and placed in a position that does not affect the RF field. The tube should have an internal diameter of approximately 6 mm and thickness of about 1.5 mm, and be flexible enough to not obstruct the rotation of the turntable.

- The plastic horn should match the speaker size of the EUT, have soft foam rubber attached to the edge, and be attached to one end of the acoustic tube, while the microphone is attached to the other end. Aligning the center of the horn with the relevant copy position relative to the EUT is crucial because this central position has a strong influence on the frequency response being measured. This can be achieved by placing the EUT in a manufacturer-provided acoustic coupler mounting fixture, with the horn as an integrated part.

- The microphone must have a flat frequency response within 1 dB in the range from 50 Hz to 20 kHz, with a minimum linear dynamic range of 50 dB. The sensitivity of the microphone and the output level of the receiver should be suitable to measure a signal-to-noise ratio of at least 40 dB at the rated output level of the EUT. The size of the microphone must be small enough to fit into the acoustic tube.

- The frequency correction circuit should calibrate the frequency response of the acoustic coupler so that the sound SINAD measurement is accurate.

A.3.3.2. Calibration

The purpose of calibrating the acoustic coupler is to determine the sound SINAD ratio, equivalent to the SINAD ratio at the receiver output.

Figure A.5 - Calibration Measurement Diagram

i. The acoustic coupler must be connected to the device, if necessary using a measurement coupler. A direct electrical connection to the output terminals of the converter will be made. The signal generator must be connected to the receiver input (or the input of the measurement coupler). The signal generator must be at the rated frequency of the receiver and modulated by normal measurement modulation.

ii. If possible, adjust the receiver volume to at least 50% of the rated output power, and if the volume adjustment is in steps, adjust to the first step providing at least 50% of the rated output power.

iii. The input signal level must be reduced until the electrical SINAD ratio reaches 20 dB, connected at position 1. Record the input signal level.

iv. With the same input signal level, measure and record the equivalent sound SINAD ratio, connected at position 2.

v. Repeat steps iii. and iv. with an electrical SINAD ratio of 14 dB, measure and record the equivalent sound SINAD ratio.

A.4. Measurement Coupler Box

A.4.1. Description

The measurement coupler box is a radio frequency combiner device combined with an integrated antenna device to combine this integrated antenna with a 50 Ω radio frequency terminal at the working frequency of the device to be measured. This allows certain measurements to be carried out using direct measurement methods. Relative measurements can only be performed at or near frequencies for which the measurement coupler box has been calibrated.

Additionally, the measurement coupler box must provide:

- A connection to an external power supply;

- An audio interface or direct connection or an acoustic coupler.

The measurement coupler box is usually provided by the manufacturer.

The operational characteristics of the measurement coupler box must comply with the following basic parameters:

- The insertion loss must not exceed 30 dB;

- The variation in insertion loss across the measurement frequency band must not exceed 2 dB;

- The circuitry attached to the RF combiner must not contain active devices and nonlinear devices;

- The VSWR at the 50 Ω connector must not exceed 1.5 in the measurement frequency band;

- The insertion loss must not depend on the position of the measurement coupler box and must not be affected by surrounding objects and people. The insertion loss must be reproducible when the device under test is removed and replaced;

- The insertion loss must remain unchanged when environmental conditions change.

The characteristics and calibration must be included in the measurement report.

A.4.2. Calibration

Calibration of the measurement coupler box establishes the relationship between the output of the signal generator and the input field strength applied to the device inside the measurement coupler box.

Calibration is valid only at a specific frequency and a specific polarization of the reference field.

Figure A.6 - Calibration Measurement Diagram

i. Using the method described in section 2.3.1.3.1, measure the sensitivity in terms of field strength, and record the value of this field strength in dBμV/m and the type of polarization used.

ii. Place the receiver in the measurement coupler box connected to the signal generator. Record the level generated by the signal generator when the SINAD is 20 dB.

iii. Calibration of the measurement coupler box is the relationship between the field strength expressed in dBμV/m and the signal generator level expressed in dBμV emf. This relationship is considered linear.

A.4.3. Implementation Method

For transmitter measurements, calibration is not required.

For receiver measurements, calibration is necessary.

To apply the desired signal level specified as field strength, it must be converted to the signal generator level (emf) using the calibration curve of the measurement coupler box. Apply this value to the signal generator.

 

Provisions on the HS Code of Terrestrial Mobile Radio Equipment and Terrestrial Radio Relay Equipment

·(Provisions)

Technical specifications for adjacent channel power measurement schemes

B.1. Technical specifications for power measurement receivers

The power measurement receiver is used to measure the power of adjacent channel transmitters. The receiver includes a mixer, oscillator, IF filter, amplifier, attenuator converter, and a level indicator as shown in Figure B.1.

Figure B.1 - Power Measurement Receiver

A calibrated rms voltmeter with dB scale can be used instead of the attenuator converter with an rms value indicator. The technical characteristics of the power measurement receiver are presented in Sections B.1.1 through B.1.4.

B.1.1 Intermediate Frequency Filter

The IF filter must fall within the selectivity characteristics limits shown in Figure B.2 below:

Figure B.2 - Intermediate Frequency Filter

Depending on the channel spacing, the selectivity characteristics must maintain a frequency distance from the nominal center frequency of the adjacent channel as set out in Table B.1.

Table B.1 - Selectivity Characteristics

Depending on the channel spacing, the attenuation points shall not exceed the tolerances provided in Tables B.2 and B.3.

Table B.2 - Attenuation Points Near the Carrier

Table B.3 - Attenuation Points Far from the Carrier

The minimum attenuation of the filter outside the 90 dB attenuation point shall be greater than or equal to 90 dB.

B.1.2 Attenuation Indicator

The attenuation indicator must have a minimum range of 80 dB and the reading accuracy must be 1 dB. For future regulations, it should reduce from 90 dB upwards.

B.1.3 RMS Level Indicator

The RMS level indicator must accurately indicate signals that are not sine waves with a peak-to-RMS ratio up to 10:1.

B.1.4 Oscillator and Amplifier

The oscillator and amplifier need to be designed such that the power measurement of the adjacent channel of an unmodulated low-noise transmitter does not exceed -90 dB with a channel spacing of 25 kHz and ≤-80 dB with a channel spacing of 12.5 kHz, compared to the carrier of the oscillator, the inherent noise of the unmodulated low-noise transmitter has little effect on the measurement result.

B.2. Spectrum Analyzer Characteristics

B.2.1 Adjacent and Interleaved Channel Power Measurements

The spectrum analyzer characteristics must meet at least the following requirements:

- The reading accuracy of the marked frequency point must be within ± 100 Hz.

- The relative amplitude measurement accuracy must be within ± 3.5 dB.

The spectrum analyzer may be adjusted to allow two components of equal amplitude separated by a frequency difference of 200 Hz to be displayed on the screen.

For statistical distribution modulations, the spectrum analyzer and integrated equipment (if applicable) must allow the determination of energy spectral density (energy over time and bandwidth) integrated over the specified bandwidth. The effective energy of all discrete components, spectral energy density, and noise power in the selected bandwidth can be summed, and the ratio measured corresponding to the carrier power. The spectrum analyzer must have a dynamic range greater than 90 dB and the phase noise in adjacent channels should not limit the adjacent channel power measurement. To confirm this, use the measurement technique in Section 2.2.3.3 to measure the adjacent channel power with a CW signal source with phase noise below -120 dBc/Hz at the center of the adjacent channel. The results obtained are as follows:

- The maximum observed adjacent channel power under these conditions shall not exceed -70 dBc.

- The maximum interleaved channel power measured under these conditions will not exceed -80 dBc.

NOTE: A resolution bandwidth of 500 Hz may be used for this measurement instead of 100 Hz to reduce measurement time.

B.2.2 Unwanted Emission Measurement

The technical specifications include the following requirements.

A resolution bandwidth of 1 kHz may be used to measure the amplitude of the signal or noise at a level 3 dB or higher than the noise of the spectrum analyzer, as displayed on the screen, with an accuracy of ±2 dB when there is a desired signal.

The relative amplitude measurement accuracy must be within ±1 dB.

For statistical distribution modulations, the spectrum analyzer and integrated equipment (if applicable) will allow the determination of actual spectral energy density (energy over time and bandwidth) integrated over the specified bandwidth.

B.3 Integrated and Combined Power Equipment

Integrated and combined power equipment is connected to the video output of the spectrum analyzer mentioned in Article B.2.

The effective energy of all discrete components, spectral energy density, and noise power in the selected bandwidth can be summed, and the ratio measured corresponding to the carrier power.

·REFERENCES

 

[1] ETSI EN 300 390 V2.1.1 (2016-03) Land Mobile Service; Radio equipment intended for the transmission of data (and speech) and using an integral antenna; Harmonised Standard covering the essential requirements of Article 3.2 of the Directive 2014/53/EU

[2] Directive 2014/53/EU of the European Parliament and of the Council of 16 April 2014 on the harmonisation of the laws of the Member States relating to the making available on the market of radio equipment and repealing Directive 1999/5/EC.

[3] Commission Implementing Decision C(2015) 5376 final of 4.8.2015 on a standardization request to the European Committee for Electrotechnical Standardization and to the European Telecommunications Standards Institute as regards radio equipment in support of Directive 2014/53/EU of the European Parliament and of the Council.

[4] ETSI EN 300 113 (V2.1.0): "Land Mobile Service; Radio equipment intended for the transmission of data (and/or speech) using constant or non-constant envelope modulation and having an antenna connector; Harmonized Standard covering the essential requirements of Article 3.2 of the Directive 2014/53/EU".

[4] ETSI EN 300 113 (V2.1.0): "Land Mobile Service; Radio equipment intended for the transmission of data (and/or speech) using constant or non-constant envelope modulation and having an antenna connector; Harmonised Standard covering the essential requirements of Article 3.2 of the Directive 2014/53/EU".