Circular No. 25/2020/TT-BTTTT Issuing "National Technical Regulations for VHF Telephones Used in Maritime Mobile Services"

 

CIRCULAR

Issuing the "National Technical Regulation on VHF Radiotelephone Equipment for Maritime Mobile Services"
pursuant to Article 52 dated August 1, 2007 of the Government detailing implementation of certain provisions of the Law on Technical Standards and Regulations;

On the basis of Law on Standards and Technical Regulations June 29, 2006;

On the basis of Law on Telecommunications November 23, 2009;

On the basis of Law on Radio Frequency November 23, 2009;

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

Decree No. 78/2018/NĐ-CP May 16, 2018 of the Government amending and supplementing certain provisions of Decree No. Decision No. 127/2007/NĐ-CP The Minister of Information and Communications issues this Circular stipulating the National Technical Regulation on VHF Radiotelephone Equipment for Maritime Mobile Services.

Decree No. Resolution No. 17/2017/NĐ-CP dated February 17, 2017 of the Government detailing 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,

This Circular promulgates the National Technical Regulation on VHF Radiotelephone Equipment for Maritime Mobile Services (QCVN 52:2020/BTTTT).

Article 1. 2. The National Technical Regulation on VHF Radiotelephone Equipment for Maritime Mobile Services, designated QCVN 52:2011/BTTTT, as stipulated in Clause 12, Article 1 of Circular No. 29/2011/TT-BTTTT dated October 26, 2011 issued by the Minister of Information and Communications regarding National Technical Regulations on Telecommunications shall cease to be effective from July 1, 2021.

Article 2. Effective Date

1. This Circular takes effect from July 1, 2021.

The Director of the Office, Heads of Departments under the Ministry of Information and Communications, Heads of provincial and municipal departments of information and communications under the central government, and organizations and individuals related to this matter are responsible for implementing this Circular./.

Article 3. - Official Gazette, Government Portal;

 

NATIONAL TECHNICAL REGULATION ON VHF RADIOTELEPHONE EQUIPMENT FOR MARITIME MOBILE SERVICES

QCVN 52:2011/BTTTT.

This national technical regulation sets forth minimum requirements for VHF radiotelephone equipment for voice communication and digital selective calling (DSC) with external antenna connections.

Foreword

NATIONAL TECHNICAL REGULATION ON VHF RADIOTELEPHONE EQUIPMENT FOR MARITIME MOBILE SERVICES TO REPLACE This regulation applies to VHF radiotelephone equipment operating in the maritime mobile service frequency band (specific frequency bands as specified in the National Radio Frequency Plan) using both 12.5 kHz and 25 kHz channels.

NATIONAL TECHNICAL REGULATION ON VHF RADIOTELEPHONE EQUIPMENT FOR MARITIME MOBILE SERVICES This regulation applies to products and goods which are VHF radiotelephone equipment for maritime mobile services with HS code as specified in Appendix D.

QCVN 52:2011/BTTTT.

This national technical regulation sets forth minimum requirements for VHF radiotelephone equipment for voice communication and digital selective calling (DSC) with external antenna connections.

Chapter 1. GENERAL PROVISIONS

1.1. Scope of Application

This national technical regulation applies to Vietnamese and foreign organizations and individuals engaged in production and business activities involving equipment within the scope of this regulation on the territory of Vietnam.

ITU Radio Regulations;

ITU-T Recommendation E.161 (2001): "Arrangement of digits, letters and symbols on telephones and other devices that can be used for gaining access to a telephone network;

1.2. Applicability

ITU-T Recommendation

1.3. Referenced Documents

.41 (1994): "Psophometer for use on telephone-type circuits";

ITU-T Recommendation E.161 (2001): "Arrangement of digits, letters and symbols on telephones and other devices that can be used for gaining access to a telephone network";

ITU-R Recommendation M.493-11 (2004): "Digital selective-calling system for use in the maritime mobile service"; OITU-R Recommendation M.541-9 (2004): "Operational procedures for the use of digital selective-calling equipment in the maritime mobile service".

IMO Resolution A.803(19): "Performance Standards for Shipborne VHF Radio Installations capable of Voice Communication and Digital Selective Calling";

IMO Resolution A.524(13): "Performance Standards for VHF Multiple Watch facilities";

IEC 61162-1 (2000): "Maritime navigation and radiocommunication equipment and systems - Digital interfaces - Part 1: Single talker and multiple listeners".

ETSI TR 100 028-1 (V1.4.1): "Electromagnetic compatibility and Radio spectrum Matters (ERM); Uncertainties in the measurement of mobile radio equipment characteristics; Part 1".

ETSI EN 300 338: "ElectroMagnetic Compatibility and Radio Spectrum Matters (ERM); Technical characteristics and methods of measurement for equipment for generation, transmission and reception of Digital Selective Calling (DSC) in the maritime MF, MF/HF and/or VHF mobile service".

ITU-R Recommendation SM.332-4 (1978): "Selectivity of receivers";

ITU-R Recommendation M.1084-4 (2001): "Interim solutions for improved efficiency in the use of the band 156-174 MHz by stations in the maritime mobile service".

1.4.1 Channel 16

(channel 16)

Frequency 156.8 MHz.

1.4. Terms and Definitions

1.4.2 Channel 70 (channel 70)

Frequency 156.525 MHz.

1.4.3 Phase modulation G3E (phase-modulation G3E)

Frequency 156,525 MHz.

1.4.3. Phase modulation G3E (phase-modulation G3E)

Phase modulation with a 6 dB/octave frequency deviation increase.

1.4.4. Phase modulation G2B (phase-modulation G2B)

Phase modulation with digital information, including a subcarrier for DSC operation.

1.4.5. Modulation index (modulation index)

The ratio between the frequency deviation and the modulating frequency.

1.4.6. Performance check (performance check)

Checking the parameters:

- Carrier frequency and power of the transmitter; and

- Receiver sensitivity (see 2.4.2).

1.5. Symbols

dBA dB corresponding to 2 x 10^-5 Pa.

1.6. Abbreviations

Chapter 2. TECHNICAL PROVISIONS

2.1. General requirements

2.1.1. Structure

The manufacturer must declare compliance with the requirements specified in Section 2.1 and must provide relevant documentation.

Mechanical structures, electrical aspects, and final assembly of the equipment must comply with good design practices in all respects, and the equipment must be designed for use on ships.

All control knobs on the equipment must be of appropriate size to facilitate operation, and the number of control knobs must be minimized to ensure effective and simple operation.

All parts of the equipment that need to be accessed during testing or maintenance must be easily accessible. Equipment components must be clearly identifiable.

Relevant technical documentation must be provided with the equipment.

Mobile maritime VHF communications services use single-frequency channels and dual-frequency channels. For dual-frequency channels, the difference between the receiving frequency and the transmitting frequency is 4.6 MHz (refer to "Radio Regulations").

The equipment may consist of one or more units and must be capable of operating on both single-frequency and dual-frequency channels with manual control (single operation). It must also be capable of operating on dual-frequency channels without manual control (dual operation).

The equipment must be capable of operating on all channels specified in note m) and e) in Appendix 18 of "Radio Regulations".

Additional VHF channels outside those specified in Appendix 18 of "Radio Regulations" may be permitted to operate, but measures must be taken to lock out any or all of these additional channels before installation on board a ship at the request of the regulatory authority. Users are not permitted to lock or unlock these additional channels.

If the equipment provides additional 12.5 kHz channels, it must comply with ITU-R M.1084-4.

The equipment must be designed to ensure that channel 70 is only used for DSC purposes and channels AIS1 and AIS2 are only used for AIS purposes, not for other purposes (see Recommendation ITU-R M.493-11 and Recommendation ITU-R M.541-9).

The equipment shall not transmit if any frequency-generating component in the transmitter has not been locked.

The equipment shall not transmit during channel switching.

2.1.2. Control and indication requirements

The equipment must have a channel selector and must indicate the registration number as in Appendix 18 of "Radio Regulations". The channel registration number must always be clearly visible under any lighting condition.

Channels 16 and 70 must be clearly marked. Selection of channel 16, and if possible channel 70, must be made through means that are easily accessible (for example, by a clearly marked switch). The transmitter output power is automatically set to its maximum value when selecting channel 16. This level can be manually reduced if necessary.

The arrangement of the digits from 0 to 9 on the surface of the equipment must comply with ITU-T Recommendation E.161.

The equipment must have supplementary control knobs and indicators such as:

- An on/off switch for the entire system with a display indicating that the system is operational;

- A non-locking Push-to-Talk button operated by hand to activate the transmitter;

- An on/off switch for the speaker;

- An on/off switch to reduce the transmitter output power below 1 W;

- A knob to control the loudness of the audio frequency power;

- A knob to reduce noise;

- A knob to dim the device illumination to 0;

- An indicator to show that the transmitter is operational.

The equipment must also meet the following requirements:

- The user shall not access any control knob whose incorrect operation would cause damage to the technical features of the equipment;

- If the control knobs that can be accessed are arranged on a separate control panel, and if there are two or more control panels, one of the control panels must take precedence over the others. If there are multiple control panels, the operation of one control panel must be displayed on another control panel.

2.1.3. Handset and speaker combination

The equipment must have a handset or microphone with an internal speaker and/or an external speaker jack. A handset must be provided if the equipment has dual-operation capability.

The equipment must be able to turn off the speaker without changing the audio frequency power supplied to the handset.

When operating in single-operation mode, the receiver output must be turned off. In dual-operation mode, only the handset operates. Measures must be taken to ensure that the dual-operation mode functions properly and preventive measures must be implemented to avoid failures caused by audio feedback or electrical feedback, which could create oscillations.

2.1.4. Safety measures

There must be measures to protect the equipment from the effects of overvoltage and overcurrent.

There must be measures to prevent damage to the equipment due to sudden polarity changes in the power supply.

There must be a method of grounding exposed metal parts of the equipment, but this method must not ground either terminal of the power supply.

All parts and conductors with DC or AC voltages (voltages other than radio frequency voltage) having peak voltages exceeding 50 V must be protected against unexpected contact and must automatically isolate from all power sources if the protective housing is removed. Alternatively, the equipment must be manufactured to prevent access to these parts operating at such voltages unless appropriate tools such as wrenches or screwdrivers are used. Clear warning labels must be affixed to both sides of the equipment and on the protective housing.

When the antenna terminals are connected to an open circuit or short circuit for a minimum period of 5 minutes, the equipment shall not be damaged.

To prevent damage caused by static voltage generated at the antenna terminals, a direct current path from the antenna terminals to the mounting bracket must be provided with an impedance not exceeding 100 kΩ.

Information stored temporarily in the devices must be retained during power loss for a period up to 60 seconds.

2.1.5. Labeling

All control knobs, components, indicators, and terminals must be clearly labeled.

The details of the power supply provided to the equipment must be clearly indicated on the equipment.

The blocks of the equipment must be clearly marked on the outer surface with information about the manufacturer, the type registration of the equipment, and the serial number of the unit.

The safe distance must be indicated on the equipment or in the user manuals supplied with the equipment.

2.1.6. Equipment Startup

After turning on the machine, the equipment must operate within a period of 5 seconds.

2.2. Technical Requirements

2.2.1. Channel Switching Time

The arrangement for channel switching must ensure that the time required to switch usage from one channel to any other channel does not exceed 5 seconds.

The time required to change from transmit to receive or vice versa must not exceed 0.3 seconds.

2.2.2. Modulation and Radiation Characteristics Classification

The equipment must use phase modulation, G3E (frequency modulation with 6 dB/octave pre-emphasis) for voice, and G2B for digital selective calling (DSC) signaling.

The equipment must be designed to operate effectively with both channel spacings of 12.5 kHz and 25 kHz.

2.2.3. Multi-watch Features

2.2.3.1. Additional Quality Standards

Radio telephones with VHF multi-watch features must comply with the following additional quality standards (see IMO Resolution A.524 (13)):

a) The equipment must have the capability to automatically scan a priority channel and an auxiliary channel. The equipment may include automatic auxiliary channel switching features, but the user shall not perform this function. Measures to lock/unlock must be provided;

b) The priority channel must be sampled even when there is a signal on the auxiliary channel, and the receiver will lock onto this channel during the detection period of the received signal;

c) The auxiliary channel must be monitored during periods when the equipment is not sampling or receiving signals on the priority channel;

d) The provided features must include manual on/off functionality for the scanning device. Additionally, it must be ensured that the receiver remains on the same channel as the transmitter throughout the entire communication period on board the vessel, for example, the scanning function can automatically turn off when the handheld set is turned off;

e) The auxiliary channel and the priority channel must be selectable at the operating position;

f) When the scanning function is active, the numbers of the two channels on which the equipment is operating must be simultaneously displayed clearly;

g) In a radio transceiver, when the scanning function is active, transmission must not occur. Upon deactivating the scanning function, both the receiver and transmitter must automatically switch to the frequency of the selected auxiliary channel;

h) A radio transceiver must have a manual control knob (e.g., pushbutton) to quickly switch the equipment operation to the priority channel;

i) At the operating position of a radio transceiver, the selected auxiliary channel must be clearly indicated when it is the active channel of the equipment.

2.2.3.2. Scanning Characteristics

When the scanning function is activated, the priority channel must be sampled for a maximum period of 2 seconds. If there is a signal on the priority channel, the receiver must remain on this channel for the duration of the received signal.

If a signal is received on the auxiliary channel, the sampling of the priority channel must continue, and thus the reception on this channel must be interrupted for the shortest possible time and not exceed 150 ms.

The receiver design must operate well during the priority channel sampling period because the reception conditions on the priority channel may differ from those on the auxiliary channel.

When there is no signal on the priority channel, and while a signal is being received on the auxiliary channel, the minimum listening time on this channel must be 850 ms.

Measures must be taken to indicate the channel receiving the signal.

2.2.4. DSC Control Interface

The equipment must have a DSC signal output impedance and input impedance of 600 Ω, symmetrical and with a separate ground wire.

If the equipment is designed as an integrated block or is fixedly mounted with a digital interface to a DSC controller, then the equipment must comply with the relevant requirements in EN 300 338, as an integrated device.

2.2.4.1. Operating Interfaces

The control interfaces must comply with IEC 61162-1.

Protocols must comply with FSI (see Appendix B). The transmitter key-off interface must be a two-wire shielded circuit to provide an open-circuit voltage of 50 V and a maximum short-circuit current of 100 mA.

Compliance with the DSC control interface is verified by successfully establishing a call through the radio interface using a working channel different from the one chosen by the equipment before the call was established. The transceiver must be connected to the DSC controller for the purpose of this test.

Commercially available connecting devices must be used. The manufacturer must provide the user with technical specifications of the connecting devices.

2.3. General Test Conditions

2.3.1. Arrangement of Test Signals for Receiver Input

Test signal sources must be connected to the receiver input so that the input impedance of the receiver is 50 Ω, regardless of whether one or multiple test signals are simultaneously fed into the receiver.

The level of the measurement signal must be displayed at the terminals connected to the receiver according to the e.m.f.

The nominal frequency of the receiver is the carrier frequency of the selected channel.

2.3.2. Mute function

Unless otherwise specified, the mute function of the receiver shall not operate during the measurement period.

2.3.3. Normal measurement modulation

For normal measurement modulation, the modulation frequency must be:

- For 25 kHz channels: 1 kHz with a frequency deviation of ±3 kHz;

- For 12.5 kHz channels: 1 kHz with a frequency deviation of ±1.5 kHz.

2.3.4. Dummy antenna

When performing measurements with a dummy antenna, this antenna must have a non-radiating 50 Ω load and no reflection.

2.3.5. Arrangement for feeding measurement signals to the transmitter input

In the Standard, the frequency-modulated audio signals fed into the transmitter must be generated by a signal generator and fed into the transmitter through connectors instead of the microphone converter.

2.3.6. Measurement channels

Unless otherwise specified, measurements shall not be performed on channel 16.

2.3.7. Measurement uncertainty and explanation of measurement results

2.3.7.1. Measurement uncertainty

Table 1 - Absolute measurement uncertainty: maximum values

For measurement methods in the Standard, measurement uncertainty values are valid with a confidence level of 95% when calculated according to the method in ETSI TR 100 028-1.

2.3.7.2. Explanation of measurement results

The interpretation of the recorded measurement results in the report must be carried out as follows:

- Compare the measured values with the corresponding requirements to determine whether the equipment meets the requirements of the Standard;

- The measurement uncertainty value for each parameter must be recorded in the measurement report;

- The recorded measurement uncertainty value for each parameter must be equal to or lower than the values in Table 1.

NOTE: The procedure using maximum measurement uncertainty values remains effective until equivalent provisions are established.

2.3.8. Measurement conditions, power supply, and temperature

2.3.8.1. Normal and extreme measurement conditions

Measurements must be performed under normal measurement conditions, and if specified, under extreme measurement conditions (applying simultaneously 2.3.10.1 and 2.3.10.2).

2.3.8.2. Measurement power supply

During the measurement, the power supply provided to the equipment must be capable of generating the normal and extreme measurement voltages specified in 2.3.9.2 and 2.3.10.2.

The internal impedance of the measurement power supply must be sufficiently low (negligible) so as not to affect the measurement results. Voltage of the power supply must be measured at the equipment input.

During the measurement period, the voltage of the power supply must be maintained within ±3% error of the initial measurement voltage.

2.3.9. Normal measurement conditions

2.3.9.1. Normal temperature and humidity

Normal measurement conditions regarding temperature and humidity include both temperature and relative humidity must be within the following limits:

- Temperature: from 15°C ¸ 35°C;

- Relative humidity: from 20% ¸ 75 %.

If the relative humidity is below 20%, it must be recorded in the measurement report.

2.3.9.2. Normal power supply

2.3.9.2.1. Grid frequency and voltage

For equipment connected to the grid, the normal measurement voltage must be the nominal grid voltage. In the Standard, the nominal voltage must be the published voltage or any designed voltage for the equipment. The frequency of the measurement voltage must be 50 Hz ± 1 Hz.

2.3.9.2.2. Battery power supply

When the equipment is designed to operate on battery power, the normal measurement voltage is the nominal battery voltage (12 V, 24 V...).

2.3.9.2.3. Other power supplies

When the equipment operates on other power supplies, the normal measurement voltage must be announced by the equipment manufacturer.

2.3.10. Extreme measurement conditions

Unless otherwise specified, extreme measurement conditions mean that the EUT must be tested simultaneously at higher temperatures and upper supply voltage limits, as well as at lower temperatures and lower supply voltage limits.

2.3.10.1. Extreme temperature

For measurements at extreme temperatures, measurements must be performed in 2.3.11, at the low extreme temperature of -15 °C and at the high extreme temperature of +55 °C.

2.3.10.2. Extreme measurement power supply

2.3.10.2.1. Grid power supply

The extreme measurement voltage for equipment connected to the grid must be the nominal grid voltage ± 10%. The frequency of the measurement voltage must be 50 Hz ± 1 Hz.

2.3.10.2.2. Battery power supply

When the equipment operates on battery power, the extreme measurement voltage must be 1.3 and 0.9 times the nominal battery voltage (12 V, 24 V...).

2.3.10.2.3. Other power supplies

When operating with other power supplies, the extreme measurement voltage must be agreed upon between the testing unit and the equipment manufacturer.

2.3.11. Procedure for measuring at extreme temperatures

The equipment must be turned off during the thermal stabilization period.

Prior to high-temperature conduction measurements, the equipment must be placed in the test chamber until thermal equilibrium is reached. Then, the equipment must be turned on for 30 minutes under high-power transmission conditions at normal voltage, and it must meet the requirements of this national technical standard.

For low-temperature measurements, the equipment must be placed in the test chamber until thermal equilibrium is reached. Then, the equipment must be turned on in standby or receive mode for 1 minute, and it must meet the requirements of the standard.

2.4. Environmental tests

2.4.1. Procedure

Environmental tests must be conducted prior to performing other measurements on the same equipment.

Unless otherwise specified, the equipment shall only be connected to power for a duration equal to that required for electrical testing. These tests shall be performed using normal measurement voltages.

2.4.2. Quality Testing

The testing includes: frequency error testing of the transmitter (see 2.5.1.1), carrier power testing of the transmitter (see 2.5.2.1) and receiver sensitivity testing (see 2.6.3.1):

- Frequency of the carrier wave of the transmitter on channel 16 must be measured when there is no modulation and the transmitter is connected to a dummy antenna (see 2.3.4). Conduct the test with the output switch set to maximum position. The frequency error must be within ±1.5 kHz;

- Carrier power of the transmitter on channel 16 must be measured when the transmitter is connected to a dummy antenna (see 2.3.4). Conduct the test with the output switch set to maximum position. The carrier power must be within 6 W and 25 W;

- Receiver sensitivity on channel 16 must be measured. Input a normally modulated test signal (see 2.3.3) into the receiver. Connect the receiver's output to an audio load and a SINAD measuring device (through a noise filter as in 2.6.3.1). Adjust the level of the test signal until the SINAD ratio equals 20 dB and adjust the receiver's audio output power to a minimum of 50% of the rated output power. The level of the test signal must not exceed +12 dBµV (e.m.f).

2.4.3. Vibration Test

2.4.3.1. Definition

This test aims to verify the ability of the equipment to withstand vibration without mechanical weakening or degradation of its characteristics.

2.4.3.2. Test Method

The EUT, along with its shock absorber, must be securely mounted on a vibration table at a typical height using supporting devices. The EUT may be suspended to compensate for weight that cannot be attached to the vibration table. Measures must be taken to minimize the influence of electromagnetic fields generated during the vibration test on the performance of the equipment.

The EUT must undergo sinusoidal vibration vertically across all frequencies between:

- 2.5 Hz and 13.2 Hz with an amplitude of ±1 mm, ±10% (maximum acceleration 7 m/s²² at 13.2 Hz);

- 13.2 Hz and 100 Hz with constant maximum acceleration of 7 m/s²².

The frequency sweep rate must be slow enough to detect resonance in any part of the EUT.

During the vibration test, resonance must be sought. If the equipment exhibits any resonance with a Q factor ≥ 5 relative to the vibration table, the vibration endurance test of the equipment must be conducted at each resonant frequency for 2 hours with the same vibration level. If the equipment has any resonance with a Q factor < 5, the vibration endurance test must be conducted only at the observed resonant frequency. If no resonance is detected, the vibration endurance test must be conducted at 30 Hz.

Quality tests must be carried out upon completion of the 2-hour vibration endurance test.

Repeat the test by subjecting the EUT to vibration in each orthogonal direction in the horizontal plane.

After completing the vibration test, inspect the equipment for any visible mechanical deformation.

2.4.3.3. Requirements

The equipment must meet the requirements of quality testing.

There must be no visible deformation of the equipment.

2.4.4. Temperature Test

2.4.4.1. Definition

The immunity of the equipment to temperature effects is its ability to maintain its initial electrical and mechanical characteristics after undergoing the following tests.

2.4.4.2. Dry Heat

2.4.4.21. Definition

This test determines the equipment's ability to operate at high temperatures and under temperature changes.

2.4.4.2 2. Measurement Method

Place the EUT in a test chamber with normal humidity and temperature. Then turn on the EUT and temperature control devices. Subsequently, raise the temperature to and maintain it at 55 °C ± 3 °C.

After a temperature test period of 10 to 16 hours in the test chamber at 55 °C ± 3 °C, perform quality testing on the EUT. Maintain the test chamber temperature at 55 °C ± 3 °C throughout the entire quality testing period. Upon completion of the test, return the EUT to normal environmental conditions or to conditions suitable for subsequent testing. The maximum rate of temperature increase or decrease in the test chamber is 1 °C/min.

2.4.4.2 3. Requirements

The equipment must meet the requirements of quality testing.

2.4.4.3. Humidity

2.4 4.3.1. Definition

This test aims to determine the equipment's ability to operate under high humidity conditions.

2.4.4.3.2. Measurement Method

Place the EUT in a test chamber with normal humidity and temperature. Then increase the temperature to 40 °C ± 2 °C and relative humidity to 93% ± 3% over a period of 3 h ± 0.5 h. Maintain these conditions for a period of 10 to 16 hours. At the end of this period, turn on the accompanying temperature control devices. After 30 minutes, turn on the EUT, or immediately after the temperature test period with the manufacturer's consent, keep the EUT operational for a minimum of 2 hours and conduct quality testing on the equipment during this time. Throughout the entire quality testing period, maintain the relative humidity and temperature of the test chamber as determined. Upon completion of the test period, leave the EUT in the test chamber, reduce the test chamber temperature back to normal over a minimum period of 1 hour. Upon completion of the entire test, return the EUT to normal environmental conditions or to conditions required for further testing. The maximum rate of temperature increase or decrease in the test chamber is 1 °C/min.

2.4.4.3.3. Requirements

The equipment must meet the requirements of quality testing.

2.4.4.4. Low Temperature Cycle

2.4.4.4.1. Definition

These tests determine the equipment's ability to operate at low temperatures, as well as its ability to start up at low temperatures.

2.4.4.4.2. Measurement Method

Place the EUT in a measurement chamber with normal temperature and relative humidity. Then reduce the room temperature and maintain it at -15 °C ± 3 °C for a period from 10 to 16 hours. After this temperature test period, the associated control devices may be turned on. Thirty minutes later, turn on the EUT and maintain its operational state for a minimum of 2 hours during which time quality testing of the equipment shall be conducted. Throughout the entire quality testing period, the temperature of the measurement chamber must be maintained at -15 °C ± 3 °C. Upon completion of the test, return the EUT to normal conditions or necessary conditions for subsequent measurements. The maximum rate of increase or decrease in the temperature of the measurement chamber is 1 °C/min.

2.4.4.4.3. Requirements

The equipment must meet the requirements of the quality testing.

2.5. Requirements for Transmitters

All measurements on the transmitter must be performed with the output power switch set to the maximum position, except where otherwise specified.

2.5.1. Frequency Error

2.5.1.1. Definition

The frequency error of the transmitter is the difference between the measured carrier frequency and its nominal value.

2.5.1.2. Measurement Method

Measure the carrier frequency when unmodulated, and when connected to a dummy antenna (see 2.3.4). Perform the measurement under normal test conditions (see 2.3.9) and limit conditions (see 2.3.10).

Conduct this measurement with the output power switch set to both maximum and minimum positions.

2.5.1.3. Limits

The frequency error must be within ±1.5 kHz.

2.5.2. Carrier Power

2.5.2.1. Definition

Carrier power is the average power delivered to a dummy antenna over one cycle of the radio frequency when there is no modulation.

The rated output power is the carrier power published by the manufacturer.

2.5.2.2. Measurement Method

Connect the transmitter to a dummy antenna (see 2.3.4) and measure the transmitted power to the dummy antenna. Perform the measurement on the highest frequency channel, the lowest frequency channel, and channel 16 under both normal test conditions (see 2.3.9) and limit conditions (see 2.3.10).

2.5.2.3. Limits

2.5.2.3.1. Normal Test Conditions

Set the output power switch to the maximum position (see 2.1.2) when measuring on channels listed in Appendix 18 (International Radio Regulations), the carrier power must be within the range of 6 W and 25 W and not deviate more than ±1.5 dB from the rated output power.

2.5.2.3.2. Limit Conditions

With the output power switch set to the maximum position, the carrier power must be maintained between 6 W and 25 W and within the range of +2 dB and -3 dB of the rated output power under limit conditions.

When the output power switch is set to the minimum position, the carrier power must be within the range of 0.1 W and 1 W.

2.5.3. Frequency Deviation

2.5.3.1. Definition

Frequency deviation is the difference between the instantaneous frequency of the modulated radio frequency signal and the carrier frequency.

2.5.3.2. Maximum Permissible Frequency Deviation

2.5.3.2.1. Measurement Method

Connect the transmitter to a dummy antenna (see 2.3.4). Measure the frequency deviation at the output using a frequency deviation meter capable of measuring the maximum deviation caused by modulation components and harmonics generated in the transmitter.

Change the modulation frequency between 100 Hz and 3 kHz. The level of the test signal should be greater than 20 dB above the level of the normal modulation test signal (see 2.3.3). Repeat the measurement with the output power switch set to both maximum and minimum positions.

2.5.3.2.2. Limits

The maximum permissible frequency deviation must be:

- For 25 kHz channels: ±5 kHz;

- For 12.5 kHz channels: ±2.5 kHz.

2.5.3.3. Reduction in Frequency Deviation at Modulation Frequencies Greater Than 3 kHz

2.5.3.3.1. Measurement Method

The transmitter operates under normal test conditions (see 2.3.9), connect the transmitter to a load as specified in 2.3.4. The transmitter is normally modulated (see 2.3.3). Maintain the input level of the modulation signal constant, change the modulation frequency between 3 kHz (see footnote) and a frequency equal to the channel spacing calculated by the device, and perform the frequency deviation measurement.

NOTE: 2.55 kHz for transmitters using 12.5 kHz channel spacing.

2.5.3.3.2. Limits

For modulation frequencies between 3 kHz (for devices operating with 25 kHz channel spacing) or 2.55 kHz (for devices operating with 12.5 kHz channel spacing) and 6 kHz, the frequency deviation must not exceed the frequency deviation at a modulation frequency of 3 kHz/2.55 kHz. For a modulation frequency of 6 kHz, the frequency deviation must not exceed 30% of the maximum permissible frequency deviation.

For modulation frequencies between 6 kHz and a frequency equal to the channel spacing calculated by the device, the frequency deviation must not exceed the limit determined by the linear response of the frequency deviation (in dB) according to the modulation frequency, starting at the point where the modulation frequency is 6 kHz with a slope of -14 dB/oct, the frequency deviation decreases as the modulation frequency increases, as shown in Figure 1.

Where:

f₁: Lowest dedicated frequency:

f₂: 3.0 kHz (for 25 kHz channel spacing); or 2.55 kHz (for 12.5 kHz channel spacing);

MPFD: Maximum permissible frequency deviation, see Section 2.5.3.2;

A: Measured frequency deviation at f₂;

f_cs: Frequency equal to the channel spacing.

Figure 1 - Frequency deviation versus modulation frequency

2.5.4. Microphone Sensitivity Including Microphone

2.5.4.1. Definition

This characteristic represents the transmitter's ability to produce full modulation when a sound frequency signal with a level corresponding to the average sound level is fed into the microphone.

2.5.4.2. Measurement Method

Select a 25 kHz channel and activate the transmitter.

Feed a 1 kHz tone signal with a sound level of 94 dBA into the microphone. Measure the resulting frequency deviation.

2.5.4.3. Limits

The frequency deviation must be between ±1.5 kHz and ±3 kHz.

2.5.5. Audio Frequency Response

2.5.5.1. Definition

Audio frequency response is the frequency deviation of the transmitter, which is a function of the modulation frequency.

2.5.5.2. Measurement Method

Feed the transmitter with a modulated signal of 1 kHz frequency, measure the frequency deviation at the output. Adjust the audio input signal level so that the frequency deviation is ±1 kHz. This is the reference point as shown in Figure 2 (1 kHz corresponds to 0 dB).

Then change the modulation frequency between 300 Hz and 3 kHz (see footnote) but keep the audio signal level unchanged as determined above.

Only conduct this measurement on one channel (see 2.3.6).

NOTE: 2,55 KHz for the transmitter used exclusively for channel spacing of 12,5 kHz.

2.5.5.3. Limits

The audio frequency response must be within the range of +1 dB and -3 dB of the straight line with a slope of 6 dB/octave passing through the reference point (see Figure 2). The upper frequency limit is 2,55 kHz for the 12,5 kHz channels.

Figure 2 - Audio Frequency Response

2.5.6. Distortion of the audio frequency emission

2.5.6.1. Definition

The distortion of the modulated emission is defined as the ratio, expressed as a percentage, between the root mean square (r.m.s.) voltage of all harmonic components of the basic frequency and the r.m.s. total voltage of the signal after linear demodulation.

2.5.6.2. Measurement Method

The transmitter generates an RF signal fed into a linear demodulator via an appropriate coupling device to achieve a subsequent compression level of 6 dB/octave.

Perform this measurement on the 25 kHz channel when the output power switch is set at both maximum and minimum positions.

2.5.6.2.1. Normal Measurement Conditions

Under normal measurement conditions (see 2.3.9), the RF signal must be successfully modulated at frequencies of 300 Hz, 500 Hz, and 1 kHz with a constant modulation index of 3.

Measure the harmonic distortion of the audio frequency signal at all aforementioned frequencies.

2.5.6.2.2. Limit Measurement Conditions

Under limit measurement conditions (applying both 2.3.10.1 and 2.3.10.2 simultaneously), perform the measurement at a frequency of 1 kHz with a frequency deviation of ± 3 kHz.

2.5.6.3. Limits

Harmonic distortion shall not exceed 10 %.

2.5.7. Adjacent Channel Power

2.5.7.1. Definition

Adjacent channel power is a portion of the total output power of the transmitter under specified modulation conditions, said power lying within a defined bandwidth centered on the nominal frequency of one of the adjacent channels.

This power is the sum of the average power due to modulation, noise, and interference generated by the transmitter.

2.5.7.2. Measurement Method

Conduct this test on the lowest frequency channel, the highest frequency channel, and channel 16.

Measure adjacent channel power using a power receiver that complies with the requirements set forth in Appendix A and Recommendation ITU-R SM 332-4.

a) The transmitter must operate at carrier power as in 2.5.2 under normal measurement conditions. Connect the transmitter's output to the power receiver's input through a connecting device such that the impedance to the transmitter is 50 Ω and the level at the power receiver's input is suitable;

b) For an unmodulated transmitter, adjust the power receiver's frequency to obtain maximum response. This is the 0 dB response point. Record the power receiver's attenuation setting and the measurement result on the measuring instrument;

Measurements can be performed with a normally modulated transmitter, in which case the measurement conditions and results must be recorded in the report;

c) Adjust the power receiver's frequency away from the carrier frequency so that the -6 dB response of the power receiver closest to the transmitter's carrier frequency appears at a position 17 kHz away from the nominal carrier frequency for 25 kHz channels or 8.25 kHz away for 12.5 kHz channels;

d) Modulate the transmitter with a frequency of 1.25 kHz at a level higher than 20 dB above the required level to produce a frequency deviation of ± 3 kHz for 25 kHz channels or 1.5 kHz for 12.5 kHz channels;

e) Adjust the power receiver's attenuation to obtain a value similar to that in step b) or have a definite relationship with the reading at step b);

f) The ratio between adjacent channel power and carrier power is the difference between two variable attenuation settings of the power receiver in steps b) and e), adjusted for any differences in meter readings;

g) Repeat the measurement with the power receiver's frequency adjusted to the opposite side of the carrier frequency.

2.5.7.3. Limits

Adjacent channel power shall not exceed:

- For 25 kHz channels: the transmitter's carrier power minus 70 dB, and need not be lower than 0.2 µW;

- For 12.5 kHz channels: the transmitter's carrier power minus 60 dB, and need not be lower than 0.2 µW.

2.5.8. Spurious Emission to Antenna

2.5.8.1. Definition

Spurious emissions are emissions on one or more frequencies outside the necessary bandwidth and spurious emissions may be reduced without affecting the corresponding information transmission. Spurious emissions include harmonic emissions, parasitic emissions, intermodulation products, and frequency conversion products, but do not include out-of-band emissions.

2.5.8.2. Measurement Method

Measure spurious emissions with an unmodulated transmitter connected to a dummy antenna (see 2.3.4).

Conduct measurements in the frequency range from 9 kHz to 2 GHz, excluding the channel on which the transmitter is operating and its adjacent channels.

Measure each spurious emission using a radio receiver or spectrum analyzer.

2.5.8.3. Limits

The power of any spurious emission on any discrete frequency shall not exceed 0.25 µW.

2.5.9. Radiated Emissions Other Than Spurious Emission to Antenna

2.5.9.1. Definition

Radiated emissions include emissions at frequencies radiated by the structure and housing of the equipment.

Spurious emissions other than spurious emissions to antenna are emissions at frequencies other than the carrier frequency and intermediate frequencies generated by the desired modulation process, these emissions being caused by conduction in wiring and accessories associated with the equipment.

2.5.9.2. Measurement Method

Place the equipment at a measurement position selected from Appendix C on a non-conductive turntable at a specified height, with a position similar to the most common usage according to the manufacturer's recommendation.

Connect the transmitter's antenna connector to a dummy antenna, see 2.3.4.

Orient the measurement antenna in vertical polarization and select the length of the measurement antenna suitable for the instantaneous frequency of the receiver.

Connect the output of the measurement antenna to the receiver.

Turn on the transmitter in the unmodulated mode, adjust the receiver's frequency over the range from 30 MHz to 2 GHz outside the frequency of the channel on which the transmitter is operating and its adjacent channels.

At each detected spurious frequency:

a) Adjust the height of the dummy antenna support within a specified range until the receiver obtains the maximum signal level;

b) Rotate the transmitter 360° in the horizontal plane until the signal level meter receives the maximum signal level;

c) Record the maximum signal level received by the signal level meter;

d) Replace the transmitter with a substitute antenna as specified in Appendix C;

e) Orient the substitute antenna in vertical polarization, select the length of the substitute antenna suitable for the frequency of the spurious component obtained;

f) Connect the substitute antenna to a calibrated signal generator;

g) Set the frequency of the calibrated signal generator equal to the frequency of the spurious component obtained;

h) If necessary, adjust the input attenuation of the signal level meter to increase its sensitivity;

i) Change the height of the test antenna support within a defined range to ensure obtaining the maximum signal;

j) Adjust the input signal level of the substitute antenna so that the signal level indicated by the signal level meter equals the remembered signal level adjusted according to the change in the input attenuation of the signal level meter;

k) Record the input signal level of the substitute antenna according to power, adjusted according to the change in the input attenuation of the signal level meter;

l) Repeat the measurement with the test antenna and the substitute antenna oriented in horizontal polarization;

m) The value of the effective radiated power of each spurious emission component is the larger of the two recorded power levels at the input of the substitute antenna, adjusted to compensate for the antenna gain if necessary;

n) Repeat the measurement with the transmitter in standby mode.

2.5.9.3. Limits

When the transmitter is in standby mode, spurious emissions and equipment enclosure radiation must not exceed 2 nW.

When the transmitter is in operating mode, spurious emissions and equipment enclosure radiation must not exceed 0.25 µW.

2.5.10. Modulation Overload of the Transmitter

2.5.10.1. Definition

The modulation overload of the transmitter is the ratio, expressed in dB, between the RF signal demodulated when there is no desired modulation and the RF signal demodulated when normal test modulation is applied.

2.5.10.2. Measurement Method

Use normal test modulation as specified in 2.3.3 for the transmitter. Feed the high-frequency signal generated by the transmitter to a linear demodulator through an appropriate combiner with a subsequent 6 dB/octave compression circuit. The time constant of this compression circuit must be at least 750 µs.

Measures must be taken to avoid the influence of low-frequency sound caused by internal noise.

Measure the signal at the output of the demodulator using an RMS voltmeter.

Turn off the modulation and measure again the level of the audio overmodulation signal at the output of the demodulator.

2.5.10.3. Limits

The level of the overmodulation signal must not exceed -40 dB on 25 kHz or 12.5 kHz channels.

2.5.11. Low-Frequency Input Characteristics of DSC

2.5.11.1. Definition

This test ensures the ability of the transmitter to accurately modulate a DSC audio signal.

2.5.11.2. Measurement Method

Perform the measurement on channel 70.

Set the transmission mode for the transmitter using DSC keying lines.

The transmitter is modulated by a single-tone audio signal of 1300 Hz with a level of 0.775 V ± 0.075 V using a DSC low-frequency input termination device.

Determine the modulation index of the transmitter. Repeat the measurement with the transmitter modulated by a tone of 2100 Hz at the same level as the previous test.

2.5.11.3. Limits

The modulation index determined in both cases must lie within the range of 1.8 to 2.2.

2.5.12. Audio Input Limitation of DSC

2.5.12.1. Definition

This test ensures that the transmitter can limit deviation in frequency when DSC input signals exceed the norm.

2.5.12.2. Measurement Method

Perform the test on channel 70.

Set the transmission mode for the transmitter using DSC keying lines.

The transmitter is modulated by a single-tone audio signal of 2100 Hz with a level of 2.45 V ± 0.3 V using a DSC low-frequency input termination device.

Determine the modulation index of the transmitter.

2.5.12.3. Limits

The modulation index must be less than 2.4.

2.5.13. Modulation Start Time

2.5.13.1. Definition

The modulation start time is the elapsed time from when the transmitter is keyed until it is accurately modulated.

2.5.13.2. Measurement Method

Perform the test on channel 70. Feed a 1300 Hz audio signal with an RMS amplitude of 0.775 V ± 0.075 V to the DSC input of the transmitter. Connect the transmitter to a wideband signal analyzer using an appropriate method.

Feed the recovered audio signal from the wideband signal analyzer to an oscilloscope with memory.

Set the vertical sensitivity of the oscilloscope so that the peak-to-peak amplitude of the recovered low-frequency signal corresponds to four divisions. The time base resolution of the oscilloscope is set to 20 ms per division. Arrange the oscilloscope to trigger at one division from the left edge of the screen.

Arrange the test setup so that when the transmitter is keyed by DSC keying lines, the oscilloscope is also triggered, see Figure 3. The oscilloscope displays the modulation activity of the transmitter and indicates when the modulation circuit of the transmitter stabilizes, see Figure 4.

Stabilization time t_set is the elapsed time from the trigger event, that is, the time from when the transmitter is keyed until the recovered signal has a constant magnitude of four divisions.

Repeat the measurement with the transmitter modulated by a 2100 Hz audio tone at the same amplitude.

2.5.13.3. Limits

The stabilization time t_set must be less than 90 ms.

Figure 3 - Test Setup

Figure 4 - Oscilloscope Output

2.5.14. Transmitter Frequency Jump

2.5.14.1. Definition

The transmitter frequency jump is the time-varying difference between the actual frequency of the transmitter and its nominal frequency when the RF output power is turned on and off.

2.5.14.2. Measurement Method

Figure 5 - Test Setup

Feed two signals into the signal analyzer via a combining circuit (see 2.3.1).

Connect the transmitter to a 50 Ω power attenuator.

Connect the output of the power attenuator to the signal analyzer via one end of the combining circuit.

The test signal generator is connected to the second input of the combining circuit.

Adjust the frequency of the measurement signal to be equal to the rated frequency of the transmitter.

The measurement signal is modulated with a 1 kHz frequency signal with a deviation of ±25 kHz.

Adjust the level of the measurement signal to 0.1% of the power of the transmitter to be measured at the input of the measurement discriminator. Maintain this signal level throughout the measurement process;

Connect the frequency deviation (fd) and amplitude deviation (ad) outputs of the measurement discriminator to a memory oscilloscope.

Set the memory oscilloscope to display the channel corresponding to the frequency deviation (fd) input with a frequency deviation ≤ ±frequency deviation of one channel, equal to the corresponding channel spacing, from the rated frequency;

Set the sweep speed of the memory oscilloscope to 10 ms/div, and configure so that the trigger occurs at 1 division from the left edge of the screen.

The screen will continuously display the 1 kHz measurement signal.

Then set the memory oscilloscope to trigger on the channel corresponding to the amplitude deviation (ad) input at a low input level, rising slope.

Then turn on the transmitter without modulation to generate a trigger pulse and image on the display screen.

The result of changing the power ratio between the measurement signal and the transmitter output will create two separate parts on the screen, one part representing the 1 kHz measurement signal, the second part representing the change in frequency of the transmitter over time:

- t_on is the moment when the 1 kHz measurement signal is completely blocked;

- The time intervals t₁ and Advanced Water-saving Irrigation₂ are determined in Table 2 to determine the appropriate limit shape;

- During the time interval t₁ and Advanced Water-saving Irrigation₂ the frequency deviation must not exceed the values given in Table 2;

- After the end of t₂, the frequency deviation must be within the frequency error limits, see 2.5.1;

- Record the results of the frequency deviation over time;

- The transmitter remains in the on state.

Set the memory oscilloscope to trigger on the channel corresponding to the amplitude deviation (ad) input at a high input level, falling slope and configure so that the trigger occurs at 1 division from the right edge of the screen:

- Then turn off the transmitter;

- t_off is the moment when the 1 kHz measurement signal begins to increase;

- The time interval t₃ is given in Table 2, t₃ is used to determine the appropriate shape;

- Before the start of t₃, the frequency deviation must be within the frequency error limits, see 2.5.1;

- Record the results of the frequency deviation over time.

On condition:

Off condition:

Figure 6 - Observation organize credit institutions, foreign bank branches are responsible for organizing the implementation of this Circular.₁1. Inspection₂, organize credit institutions, foreign bank branches are responsible for organizing the implementation of this Circular.₃ on the memory oscilloscope

2.5.14.3. Limits

organize credit institutions, foreign bank branches are responsible for organizing the implementation of this Circular._on: according to the measurement method described in 2.6.10.2, the on time t_on of the transmitter is determined by the state when the output power, measured at the antenna port, exceeds 0.1% of the rated power.

organize credit institutions, foreign bank branches are responsible for organizing the implementation of this Circular.₁: the time period starting at t_on and ending at the time given in Table 2.

organize credit institutions, foreign bank branches are responsible for organizing the implementation of this Circular.₂: the time period starting at the end time of t₁ and ending at the time given in Table 2.

organize credit institutions, foreign bank branches are responsible for organizing the implementation of this Circular._off: the off time is determined by the state when the output power of the transmitter drops below 0.1% of the rated power.

organize credit institutions, foreign bank branches are responsible for organizing the implementation of this Circular.₃: the time period ending at t_off and starting at the time given in Table 2.

Table 2 - Time limits

2.6. Requirements for receivers

2.6.1. Rated audio frequency output power and harmonic distortion

2.6.1.1. Definition

Harmonic distortion at the receiver output is defined as the ratio, expressed in %, between the root mean square (r.m.s.) voltage total of all harmonic components of the modulated audio frequency signal and the r.m.s. voltage total of the signal at the receiver.

The rated audio frequency output power is the value specified by the manufacturer as the maximum output power at the receiver output, at which the requirements of the standard must be met.

2.6.1.2. Measurement Method

Apply a measurement signal with a level of +100 dBµV, at the carrier frequency equal to the rated frequency of the receiver and modulated with normal measurement modulation (see 2.3.3) to the antenna port of the receiver under conditions as in 2.3.1.

For each measurement, adjust the audio frequency of the receiver to achieve the rated value, with a simulated load simulating the operating load of the receiver (see 2.6.1.1). The value of this simulated load is specified by the manufacturer.

Under normal measurement conditions (see 2.2.3), the measurement signal is modulated sequentially at frequencies of 300 Hz, 500 Hz, and 1 kHz with a constant modulation index of 3 (the ratio between the frequency deviation and the modulation frequency). Measure harmonic distortion and audio frequency output power at all frequencies mentioned above.

Under limit measurement conditions (simultaneous application of 2.2.4.1 and 2.2.4.2), perform the measurement at the rated frequency of the receiver and at the rated frequency ±1.5 kHz. For these measurements, the modulation frequency will be 1 kHz and the frequency deviation will be ±3 kHz.

2.6.1.3. Limits

The minimum rated audio frequency output power is:

- 2 W at the speaker;

- 1 mW at the earphone of the handheld unit.

Harmonic distortion shall not exceed 10 %.

2.6.2. Audio frequency response

2.6.2.1. Definition

Audio frequency response is the change in the output level of the audio frequency of the receiver as a function of the modulation frequency of the radio frequency signal with a constant frequency deviation applied to the receiver input.

2.6.2.2. Measurement Method

Apply a measurement signal with a level of +60 dBµV (e.m.f) at the carrier frequency equal to the rated frequency of the receiver, modulated with normal measurement modulation (see 2.3.3) to the antenna port of the receiver under conditions as in 2.3.1.

Adjust the audio frequency power level of the receiver so that it produces an output power level equal to 50% of the rated output power (see 2.6.1). Maintain this setting throughout the measurement. ||| Then reduce the frequency deviation to 1 kHz, and the corresponding output audio level at this frequency shall be the reference point as shown in Figure 7 (1 kHz corresponds to 0 dB).

||| Keep the frequency deviation constant, change the modulation frequency between 300 Hz and 3 kHz, and measure the output level.

||| Repeat the measurement with the test signal at the receiver's rated frequency ±1.5 kHz.

||| Perform this test only on one channel (see 2.6.2.3).

||| 2.6.2.3. Limits 2.3.6).

||| The audio frequency response shall not deviate more than +1 dB or -3 dB from the output level characteristic curve as a function of the audio frequency passing through the point 1 kHz with a slope of 6 dB/oct (see Figure 7).

||| Figure 7 - Audio Frequency Response

||| 2.6.3. Maximum Usable Sensitivity

||| 2.6.3.1. Definition

||| The maximum usable sensitivity of the receiver is the minimum signal level (e.m.f.) at the receiver's rated frequency when fed with a normally modulated test signal (see 2.3.3), which will produce:

||| - In all cases, the audio output power level equal to 50% of the rated output power (see 2.6.1); and ||| - A SINAD ratio = 20 dB, measured at the receiver's audio output port through a voice noise filter circuit as recommended in ITU-T O.41.

||| 2.6.3.2. Measurement Method ||| Conduct the measurement on the lowest frequency channel, the highest frequency channel, and channel 16.

||| The test signal at the carrier frequency is equal to the receiver's rated frequency, normally modulated (see 2.3.3). Feed this test signal to the receiver. Connect an audio load and a SINAD measuring device (through a noise filter circuit as specified in 2.6.3.1) to the receiver's audio output port.

||| By using the noise filter circuit along with adjusting the receiver's audio frequency power level to 50% of the rated output power, adjust the level of the test signal until the SINAD ratio = 20 dB is achieved. Under these conditions, the level of the test signal at the input is the value of the maximum usable sensitivity.

||| Conduct the measurement under normal test conditions (see 2.3.9) and limit conditions (apply simultaneously).

||| Under limit test conditions, for sensitivity values, the permissible variation of the receiver's audio output power must be within ±3 dB of 50% of the rated output power. ||| 2.6.3.3. Limits

||| Under normal test conditions, the maximum usable sensitivity for 25 kHz and 12.5 kHz channels shall not exceed +6 dBµV (e.m.f) and shall not exceed +12 dBµV (e.m.f) under limit test conditions.

||| 2.6.4. Co-channel Interference Rejection 2.3.10.1 and 2.3.10.2).

||| 2.6.4.1. Definition

||| Co-channel interference rejection is the ability of the receiver to receive the desired modulated signal at the receiver's rated frequency without being degraded beyond a given threshold due to the presence of an undesired modulated signal also at the receiver's rated frequency.

||| 2.6.4.2. Measurement Method

||| Feed two input signals to the receiver through a combining network (see 2.3.1). The desired signal is a normally modulated signal (see 2.3.3). The undesired signal is modulated at 400 Hz with a frequency deviation of ±3 kHz. Both input signals are at the receiver's rated frequency to be tested. Repeat the measurement with the undesired signal shifted ±3 kHz.

||| Set the level of the desired signal to the value corresponding to the measured maximum usable sensitivity (see 2.6.3). Then adjust the amplitude of the undesired signal until the SINAD ratio at the receiver's output decreases to 14 dB.

||| The co-channel interference rejection ratio is the ratio in dB between the level of the undesired signal and the level of the desired signal at the receiver's input. At this interference rejection level, the SINAD ratio decreases to the specified value.

||| 2.6.4.3. Limits

||| The co-channel interference rejection ratio at any frequency of the undesired signal within the defined frequency band must lie within: ||| - -10 dB and 0 dB for 25 kHz channels; ||| - -12 dB and 0 dB for 12.5 kHz channels.

||| 2.6.5. Adjacent Channel Selectivity ||| 2.6.5.1. Definition

||| Adjacent channel selectivity is the ability of the receiver to receive the desired modulated signal without being degraded beyond a given threshold due to the presence of an undesired modulated signal at a frequency offset from the desired signal frequency by the nominal channel spacing.

||| 2.6.5.2. Measurement Method

||| Feed two input signals to the receiver through a combining circuit (see 2.3.1). The desired signal has a frequency equal to the receiver's rated frequency, normally modulated (see 2.3.3). The undesired signal is modulated at 400 Hz with a frequency deviation of ±3 kHz for 25 kHz channels or 1.5 kHz for 12.5 kHz channels, this signal has a frequency of the channel immediately above the desired signal.

||| After setting the level of the desired signal to the value corresponding to the measured maximum usable sensitivity (see 2.6.3), then adjust the amplitude of the undesired signal until the SINAD ratio at the receiver's output decreases to 14 dB. Repeat the measurement with the frequency of the undesired signal at the frequency of the channel immediately below the desired signal.

||| The adjacent channel selectivity is the lower of the two ratios between the level of the undesired signal and the level of the desired signal at the receiver's input at frequencies higher and lower than the desired signal frequency, expressed in dB.

||| Repeat the measurement under limit test conditions (apply simultaneously 2.3.10.1 and 2.3.10.2) with the level of the desired signal set to the value corresponding to the maximum usable sensitivity also under these conditions.

||| 2.6.5.3. Limits

||| For 25 kHz channels: Under normal test conditions, the adjacent channel selectivity shall not be less than 70 dB, and not less than 60 dB under limit test conditions.

||| For 12.5 kHz channels: Under normal test conditions, the adjacent channel selectivity shall not be less than 60 dB, and not less than 50 dB under limit test conditions.

||| Conduct the measurement under normal test conditions (see 2.3.9) and limit conditions (apply simultaneously).

||| 2.6.6. Image Rejection ||| 2.6.6.1. Definition ||| Image rejection is the ability of the receiver to distinguish the desired modulated signal at the receiver's rated frequency from an undesired signal at any other frequency with a receiving response.

||| 2.6.5. Adjacent Channel Selectivity ||| 2.6.6.2. Measurement Method

||| Feed two signals into the receiver through a combining circuit (see 2.3.1).

Repeat the measurement under limit testing conditions (applying both 2.3.10.1 and 2.3.10.2) with the level of the desired signal set to the value corresponding to the maximum available sensitivity also under these conditions. 2.6.5.3. Limits

Channels 25 kHz: Under normal testing conditions, adjacent channel selectivity must not be less than 70 dB, and must not be less than 60 dB under limit testing conditions.

Channels 12,5 kHz: Under normal testing conditions, adjacent channel selectivity must not be less than 60 dB, and must not be less than 50 dB under limit testing conditions.

2.6.6. Spurious response rejection

2.6.6.1. Definition

Spurious response rejection is the ability of the receiver to distinguish the desired modulated signal at the assigned frequency from an unwanted signal at any other frequency within the receiver's response.

2.6.6.2. Measurement method

Feed two signals into the receiver through a combining circuit (see

2.7.2.1. Definition 2.3.1). The desired signal is the signal at the designated frequency of the receiver and is normally modulated for measurement (see 2.3.3).

The undesired signal is unmodulated at 400 Hz with a frequency deviation of ±3 kHz.

||| 2.6.5. Adjacent Channel Selectivity 2.7.3). Adjust the level of the undesired signal by +86 dBµV (e.m.f). Then sweep the frequency over the range from 100 kHz to 2 GHz.

At any false response frequency, adjust the input level until the SINAD ratio decreases to 14 dB.

False response suppression is the ratio, expressed in dB, between the level of the undesired signal and the level of the desired signal at the receiver input. At this value, the SINAD ratio decreases to the specified value.

2.6.6.3. Limitations

At any frequency more than 25 kHz away from the receiver's designated frequency, the false response suppression ratio must not be less than 70 dB.

2.6.7. Intermodulation Response

2.6.7.1. Definition

The intermodulation response is the ability of the receiver to receive the desired modulated signal without a reduction exceeding a predetermined threshold due to the presence of multiple undesired signals having specific frequency relationships with the desired signal frequency.

2.6.7.2. Measurement Method

Feed three signal generators A, B, and C into the receiver through a combining circuit (see 2.3.1). The desired signal A has a frequency equal to the receiver's designated frequency and is normally modulated for measurement (see 2.3.3). The undesired signal B is unmodulated and has a frequency 50 kHz higher (or lower) than the receiver's designated frequency. The second undesired signal C is modulated at 400 Hz with a frequency deviation of ±3 kHz and has a frequency 100 kHz higher (or lower) than the receiver's designated frequency.

||| 2.6.5. Adjacent Channel Selectivity 2.6.3). Adjust the levels of the two undesired signals to be equal and adjust until the SINAD ratio at the receiver output decreases to 14 dB. Slightly adjust the frequency of signal B to create maximum SINAD ratio reduction. The levels of the two undesired signals will then be readjusted to restore the SINAD ratio = 14 dB.

The intermodulation response is the ratio, expressed in dB, between the levels of the undesired signals and the level of the desired signal at the receiver input, when the SINAD ratio decreases to the specified value.

2.6.7.3. Limitations

The intermodulation response ratio must be greater than 68 dB.

2.6.8. Blocking Characteristics

2.6.8.1. Definition

The blocking characteristics are the change (usually a reduction) in the desired output power of the receiver or the reduction in the SINAD ratio caused by an undesired signal at another frequency.

2.6.8.2. Measurement Method

2.7.2.1. Definition 2.3.1). The desired signal is the signal at the receiver's designated frequency, normally modulated for measurement (see 2.3.3). Initially, turn off the undesired signal and set the level of the desired signal to the value corresponding to the maximum available sensitivity.

If possible, adjust the audio frequency power to 50% of the rated output power, if adjusting in steps, then the minimum output power at the first step should be 50% of the rated output power. The undesired signal is unmodulated and swept over the range of +1 MHz and +10 MHz, and between -1 MHz and -10 MHz relative to the receiver's designated frequency. The input level of the undesired signal, at all frequencies within the above range, will be adjusted to cause:

a) A 3 dB reduction in the audio frequency output level of the desired signal; or

b) The SINAD ratio to decrease to 14 dB using a noise filter circuit as described in ITU-T Recommendation O.41, and any reduction occurring before that is recorded.

2.6.8.3. Limitations

The blocking characteristic, for any frequency within the specified frequency range, must not be less than 90 dBµV, except at frequencies with false responses (see 2.6.6).

2.6.9. Spurious Emission Leakage

2.6.9.1. Definition

Spurious emissions leakage from the receiver are components emitted at any frequency appearing at the receiver's input port.

2.6.9.2. Measurement Method

The level of spurious emissions must be the measured power level at the antenna.

Measure spurious emissions leakage according to the power level of any discrete signal at the input terminals of the receiver. Connect these terminals to a spectrum analyzer or voltage-selective measuring instrument with an input impedance of 50 Ω and turn on the receiver.

If the measuring device is not calibrated for input power level, then the level of any spurious emission component measured must be determined by an alternative method using a signal generator.

Measurements are performed over the frequency range from 9 kHz to 2 GHz.

2.6.9.3. Limitations

The power of any spurious emission component in the frequency range from 9 kHz to 2 GHz must not exceed 2 nW.

2.6.10. Spurious Radiation Emissions

2.6.10.1. Definition

Spurious radiation emissions from the receiver are components emitted at any frequency radiated from the housing and structure of the equipment.

2.6.10.2. Measurement Method

At a measurement position selected according to Appendix C, place the equipment on an insulated stand at a specified height, at the position closest to normal use as specified by the manufacturer.

Orient the test antenna in vertical polarization, select the length of the test antenna chosen corresponding to the instantaneous frequency of the receiver under test.

Connect the output of the measurement antenna to the receiver.

Turn on the receiver in the unmodulated mode, adjust the frequency of the receiver under test within the frequency range from 30 MHz to 2 GHz.

At each frequency where a spurious emission component is detected:

a) Adjust the height of the test antenna within the specified height range until the receiver under test receives the maximum signal level;

b) Then rotate the receiver 360° in the horizontal plane until the receiver under test receives the maximum signal level;

c) Record the maximum signal level received by the signal level meter;

d) Replace the receiver with a substitute antenna as in Appendix C;

e) Orient the substitute antenna in vertical polarization, adjust the length of the substitute antenna corresponding to the frequency of the detected spurious component;

f) Connect the substitute antenna to a calibrated signal generator;

g) Set the frequency of the calibrated signal generator to the frequency of the detected spurious component;

h) If necessary, adjust the input attenuation of the receiver under test to increase its sensitivity;

i) Adjust the height of the test antenna within the specified range to ensure receiving the maximum signal.

j) Adjust the level of the substitute antenna input signal so that the signal level measured by the receiver matches the signal level recorded when measuring the dummy component, adjusted according to changes in the receiver's input attenuation setting;

k) Record the substitute antenna input level according to power, adjusted according to changes in the receiver's input attenuation setting;

l) Repeat the measurement with the test antenna orientation and the substitute antenna oriented for horizontal polarization;

m) The effective radiated power value of the dummy components is the higher of the two power levels of the dummy components recorded at the substitute antenna input, adjusted according to the antenna gain if necessary;

2.6.10.3. Limits

The power of any spurious radiation within the frequency band from 30 MHz to 2 GHz must not exceed 2 nW;

2.6.11. Receiver Noise

2.6.11.1. Definition

Receiver noise is defined as the ratio, expressed in dB, between the audio power of the noise and interference caused by false effects of the power supply system or other causes, and the audio power generated by a high-frequency test signal with a normal modulation level applied to the receiver's antenna input;

2.6.11.2. Measurement Method

Apply a test signal with a level of +30 dBµV at the carrier frequency equal to the receiver's nominal frequency, normally modulated as in 2.3.3 to the receiver input. Connect an audio load to the receiver output port. Set the audio power so that it produces the nominal output power level as in 2.6.1.

Measure the voltage level of the output signal using an RMS voltmeter with a minimum bandwidth (-6 dB) of 20 kHz. Turn off the modulation and measure again the output audio power level;

2.6.11.3. Limits

The receiver noise must not exceed -40 dB relative to the level of the modulated signal;

2.6.12. Audio Mute Function

2.6.12.1. Definition

The purpose of this function is to mute the receiver's audio output signal when the signal level at the receiver's antenna input is below a predetermined value;

2.6.12.2. Measurement Method

Perform the following measurement method:

a) Do not activate (turn off) the audio mute function, apply a test signal with a level of +30 dBµV at the carrier frequency equal to the receiver's nominal frequency and normally modulated as in 2.3.3 to the receiver antenna port. Connect an audio load and a real noise filter circuit (see 2.6.3.1) to the receiver output port. Adjust the receiver's audio power level to produce the nominal output power level as in 2.6.1;

Measure the output signal level using an RMS voltmeter;

Then turn off the input signal, activate (turn on) the audio mute function and remeasure the audio output level;

b) Do not activate (turn off) the audio mute function again, apply a test signal with a level of +6 dBµV normally modulated to the receiver antenna port and set the receiver to produce a level of 50% of the nominal output power. The input signal level will be reduced, activate (turn on) the audio mute function. Then increase the input signal level until the output power level equals the previous level. Afterward, measure the SINAD ratio and the input signal level;

c) Do not activate this function and apply a normally modulated test signal with a level of +6 dBµV (e.m.f.) to the receiver antenna port, adjust the receiver to produce 50% of the nominal output power. Activate (turn on) the audio mute function at maximum position and increase the input signal level until the output power equals 50% of the nominal output power (Applicable only for equipment with continuously adjustable audio mute function);

2.6.12.3. Limits

Under conditions as in a) of 2.6.12.2, the audio output power must not exceed -40 dB relative to the nominal output power;

Under conditions as in b) of 2.6.12.2, the input level must not exceed +6 dBµV (e.m.f.);

Under conditions as in c) of 2.6.12.2, the input signal must not exceed +6 dBµV (e.m.f.) when the audio mute function is set at maximum position;

2.6.13. Audio Mute Delay

2.6.13.1. Definition

Audio mute delay is the difference, expressed in dB, between the input signal levels of the receiver when the audio mute function is turned off and on;

2.6.13.2. Measurement Method

If there is an external control switch for the audio mute function, it must be set to fully activate the function. When activating (turning on) the audio mute function, apply an unmodulated input signal at the carrier frequency equal to the receiver's nominal frequency to the receiver antenna port at a sufficiently low level to avoid activating the audio mute function. Increase the input signal level to just enough to activate the audio mute function. Record this input signal level. While maintaining the audio mute function activated, gradually reduce the input signal level until the receiver's audio output is muted again;

2.6.13.3. Limits

The audio mute delay must be within the range of 3 dB to 6 dB;

2.6.14. Multiple Observation Characteristics

2.6.14.1. Definition

The scan cycle is the time interval between the beginnings of two consecutive samples on the priority channel when there is no signal on that channel;

The dwell time on the priority channel is the duration from the start to the end of any sample on the priority channel when there is no signal on that channel;

The dwell time on the supplementary channel is the duration from the start to the end of any sample on that channel;

2.6.14.2. Measurement Method

Adjust the scanner to prioritize on a preferred channel and an additional channel. These features may not be present on the DSC channel (channel 70).

Perform the function to mute the sound and adjust so that the sound of the receiver is muted on both channels. Apply a test signal at the carrier frequency equal to the assigned frequency of the additional channel of the receiver, modulated with normal test modulation (see 2.3.3) to the receiver through a combining circuit (see 2.3.1). The second test signal has a frequency equal to the assigned frequency of the preferred channel and is unmodulated, this signal is also fed into the receiver through another input of the combining circuit. The levels of the two test signals at the receiver input are +12 dBµV (e.m.f). Connect an oscilloscope with memory to the audio output. Initially, turn off the test signal output on the preferred channel. Start the scanning process and observe the output signal on the oscilloscope. Measure the time between audio signal pulses and the length of the audio signal pulses. Turn on the test signal on the preferred channel, the scanning process will stop on the preferred channel after receiving the last audio signal pulse and during the stopping time on the preferred channel. Conduct the measurement with the additional channel as a simplex channel and repeat the measurement with the additional channel as a duplex channel. 2.6.14.3. Limits The scanning cycle must not exceed 2 seconds.

The stopping time on the preferred channel must not exceed 150 milliseconds.

The stopping time on the additional channel must be within the range of 850 milliseconds and 2 seconds, this stopping time is determined as the idle time between two clusters of output audio signal pulses.

2.6.15. Audio output characteristics for DSC

2.6.15.1. Definition

The DSC audio characteristic is the level of two DSC tones at the DSC audio output terminals when the receiver is receiving an accurately modulated DSC signal.

2.6.15.2. Measurement method

Feed a test signal at the assigned carrier frequency to the receiver input. This signal is modulated with a tone of 1300 Hz with a modulation index of 2. Set the signal generator level to +26 dBµV.

The DSC audio output terminals have a load of 600 Ω.

Perform the test on channel 70.

Measure the audio level at these terminals.

Repeat the measurements with a test signal modulated with a tone of 2100 Hz while maintaining a modulation index of 2.

2.6.15.3. Limits

The signal level delivered through the load at the DSC output terminals must be within the range of 0.55 V (rms) and 1.1 V (rms).

2.7. Duplex operation

If the equipment is designed for duplex operation, during conformity testing, a duplex filter must be installed and the following additional tests must be performed to ensure proper operation.

2.7.1. Receiver sensitivity reduction due to simultaneous reception and transmission

2.7.1.1. Definition

The reduction in receiver sensitivity is caused by power transfer from the transmitter to the receiver due to coupling effects.

This reduction is expressed as the difference in maximum available sensitivity levels in dB when receiving and transmitting simultaneously and separately.

2.7.1.2. Measurement method

The antenna port of the equipment including the receiver, transmitter, and duplex filter is connected through a combiner to a dummy antenna specified in the standard.

A signal generator with normal test modulation (as in 2.3.3) is connected to the combiner without affecting impedance matching.

The transmitter must operate at the output carrier power as specified in 2.5.2, modulated by a 400 Hz signal with a deviation of ±3 kHz: 2.3.4.

- Measure the receiver sensitivity according to the standard; - Record the output level of the signal generator as C dBµV (e.m.f);

- Turn off the transmitter, and measure the receiver sensitivity again; - Record the output level of the signal generator as D dBµV (e.m.f);

- The reduction in sensitivity is the difference between the values of C and D. 2.6.3;

2.7.1.3. Limits

The reduction in sensitivity must not exceed 3 dB. The maximum available sensitivity under simultaneous receiving and transmitting conditions must not exceed the limits specified in the standard.

2.7.2. Internal mixing in duplex transceivers

2.7.2.1. Definition

Internal mixing in duplex transceivers can lead to undesired receiver sensitivity at certain frequencies.

2.7.2.2. Measurement method 2.6.3.3.

The antenna port of the equipment including the receiver, transmitter, and duplex filter is connected to a dummy antenna through a combiner as specified in the standard.êUse a test port to switch the signal to the receiver.

The internal mixing of dual-transceiver units will result in undesired receiver sensitivity at certain frequencies.

2.7.2.2. Measurement method

The antenna port of the equipment including the receiver, transmitter, and dual-band filter is connected to a dummy antenna via a combiner as in

Use a test port to switch the signal to the receiver. 2.3.4.

C.1. Test position and general layout for measurements related to radiation field

Adjust the frequency of the device to the frequency of channel 18, with the transmitter operating in an unmodulated carrier wave mode at the specified output power as provided in 2.5.2.

Conduct the measurement according to 2.6.6.2 using the test port as the receiver port. Perform the measurements in the following frequency bands:

- 161.5 MHz - 2 x f_{international} - 1 MHz to 161.5 MHz - 2 x f_{international} + 1 MHz;

- 161.5 MHz + 2 x f_{international} - 1 MHz to 161.5 MHz + 2 x f_{international} + 1 MHz;

- 155.9 to 157.9 MHz.

f_{international} is the center frequency of the first intermediate frequency band published by the manufacturer.

2.7.2.3. Limits

At any frequency where a response appears, the ratio between the signal levels determined according to 2.6.6.2 must not be less than 70 dB.

3. MANAGEMENT PROVISIONS

3.1. The VHF telephone equipment within the scope of regulation of Article 1.1 must comply with the technical requirements stipulated in this Standard and declare conformity in accordance with current regulations.

3.2. Testing/measurement for technical requirements of Article 2.5.1, 2.5.2, 2.5.3, 2.5.7, 2.5.8, 2.5.9, 2.6.9 and 2.6.10 shall be carried out by domestic testing laboratories designated, or foreign testing laboratories recognized.

3.3. Other technical requirements outside those specified in Article 3.2 of this Standard, organizations and individuals are permitted to use the results of testing/measurement from domestic testing laboratories designated, or foreign testing laboratories recognized, or domestic and foreign testing laboratories recognized in compliance with ISO 17025 standard, or the results of testing/measurement from the manufacturer.

4. RESPONSIBILITIES OF ORGANIZATIONS AND INDIVIDUALS

Organizations and individuals related have the responsibility to implement the provisions on declaring conformity of VHF telephone equipment within the scope of regulation of this Standard and are subject to inspection by the State Management Authority in accordance with current regulations.

Chapter 5. ORGANIZATION OF IMPLEMENTATION

5.1. The Telecommunications Administration and Provincial Departments of Information and Communications are responsible for organizing the implementation of this Standard.

5.2. This Standard replaces the National Technical Regulation QCVN 52:2011/BTTTT "National Technical Regulation on VHF Telephone Equipment Used for Marine Mobile Services".

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

5.4. During the implementation of this Standard, if any issues arise or difficulties occur, organizations and individuals concerned shall report in writing to the Ministry of Information and Communications (Science and Technology Department) for guidance and resolution./.

ANNEX A

Product Name, Goods According to QCVN

Adjacent Channel Power Measurement Receiver

A.1. Technical Specifications of the Adjacent Channel Power Measurement Receiver

The adjacent channel power measurement receiver includes a mixer, an intermediate frequency (IF) filter, an oscillator generator, an amplifier, a variable attenuator, and an RMS meter. If the variable attenuator and RMS meter are not used, a calibrated RMS meter can be employed. The technical specifications of the adjacent channel power measurement receiver are defined in the sections below (see Recommendation ITU-R SM 332-4).

A.1.1. Intermediate Frequency Filter

The IF filter must fall within the limits of the selectivity characteristic shown in Figure A.1.

Figure A.1 - Selectivity Characteristic Limits of the Intermediate Frequency Filter

The selectivity characteristic will maintain the frequency spacing given in Table A.1 relative to the nominal center frequency of the adjacent channel.

Table A.1 - Selectivity Characteristics

Attenuation points must not exceed the tolerances given in Tables A.2 and A.3.

Table A.2 - Attenuation Points Near the Carrier

Table A.3 - Attenuation Points Far from the Carrier

The minimum attenuation outside the 90 dB attenuation point must be equal to or greater than 90 dB,

A.1.2. Attenuation Meter

The attenuation meter must have a minimum range of 80 dB and a reading accuracy of 1 dB.

A.1.3. RMS Value Meter

The device must accurately indicate up to a 10:1 ratio between peak value and RMS value for non-sinusoidal signals.

A.1.4. Oscillator Generator and Amplifier

The oscillator generator and amplifier must be designed such that when measuring the adjacent channel power of an unmodulated low-noise transmitter, the inherent noise of the equipment does not affect the measurement result, producing a measured value ≤ -90 dB.

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

Product Name, Goods According to QCVN

Protocol for IEC 1162-1 commands regarding frequency setting information

B.1. Frequency Setting InformationầThis command is used to set the frequency, operating mode, and power level of a radio telephone, to read the frequency, mode, power, and understand the setting commands.

Figure B.1 - Frequency Setting Information

NOTE 1: Operating modes:

- d = F3E/G3E single-sideband, telephone;

- e = F3E/G3E double-sideband, telephone;

- m = J3E, telephone;

- o = H3E, telephone;

- q = F1B/J2B FEC NBDP

TELEX/teleprinter;, - s = F1B/J2B ARQ NBDP, TELEX/teleprinter,

- t = F1B/J2B telex, teleprinter/DSC;

- w = F1B/J2B, teleprinter/DSC;无效 - A1A Morse, tape recorder:

- A1A Morse, morse key/headset:

- x - | = F1C/F2C/F3C, fax machine;amendc) Participating in assessing the conditions of food production and business establishments in the area according to the分级回复

- - null for no information.

NOTE 2: Frequency increases in steps of 100 Hz:

- MF/HF telephone channels must have the first three digits following the ITU channel numbers with leading zeros as specified;shall - MF/HF teletype channels must have the first four digits, frequency tables in the second and third digits, ITU channel numbers in the fourth to sixth digits; each digit has leading zeros as specified;

- VHF channels must have the first nine digits followed by the channel number with leading zeros as specified.

NOTE 3: For paired frequencies, only the transmission frequency needs to be included; null for reception frequency. For reception frequencies, the transmission frequency field must be null.

Radiation Measurements

C.1. Measurement Position and General Layout for Measurements Related to the Radiation Field

C.1.1. Outdoor Measurement Position

Annex C

Product Name, Goods According to QCVN

The outdoor measurement position must be on a reasonable surface or ground. At a measurement point, the ground plane must have a minimum diameter of 5 meters. In the middle of the ground plane, there is a non-conductive support pole that can rotate 360° horizontally, used to support the measurement sample at a height of 1.5 meters above the ground plane. The measurement position must be wide enough to allow the installation of a transmitting antenna or measurement at a distance of λ/2 or 3 meters (choose the larger value). The actual distance must be recorded along with the measurement results conducted at that location.

C.1.1. Outdoor test position

The outdoor test position must be on a reasonable surface or ground. At a point on the test position, the ground plane must have a minimum diameter of 5 meters. In the center of the ground plane, there is a non-conductive support pole that can rotate 360° horizontally, this pole is used to hold the test sample at a height of 1.5 meters above the ground plane. The test position must be wide enough to erect a transmitting antenna or measure at a distance of λ/2 or 3 meters (choose the larger value). The actual distance must be recorded along with the test results conducted at that position.

The outdoor measurement position must be on a reasonable surface or on the ground. At a point on the measurement position, the plane surface must have a minimum diameter of 5 meters. In the center of the surface, there is a non-conductive support pole that can rotate 360° horizontally; this pole is used to support the measurement sample at a height of 1.5 meters above the surface. The measurement position must be wide enough to allow for the erection of a transmitting antenna or measurement at a distance of λ/2 or 3 meters (selecting the larger value). The actual distance must be recorded along with the measurement results conducted at that position.

Measures must be taken to ensure that reflections from external shielding objects and reflections from the ground surface do not affect the measurement results.

Figure C.1 - Outdoor Measurement Position

NOTE:

1. Equipment to be measured;

2. Measurement antenna:

3. High-pass filter (in case of strong basic Tx radiation):

4. Spectrum analyzer, or receiver measuring instrument.

C.1.2. Measurement Antenna

The measurement antenna is used to receive radiation from the test sample and substitute antennas when using the measurement position for radiation measurements: if necessary, it can be used as a transmitting antenna when using the measurement position for receiver characteristic measurements.

This antenna is mounted on a support pole allowing the antenna to be used in vertical or horizontal polarization, and the height of the antenna above the ground can vary between 1 m and 4 m. It is best to use a directional measurement antenna. The size of the measurement antenna along the measurement axes should not exceed 20% of the measurement distance.

For radiation measurements from receivers and transmitters, connect the measurement antenna to the receiver measuring instrument, which has the ability to detect any frequency required for surveying, and accurately measure the relative level of the signal at its input. For receiver radiation sensitivity measurements, connect the measurement antenna to the signal generator.

C.1.3. Substitute Antenna

When performing measurements up to 1 GHz, the substitute antenna must be a half-wave dipole, resonant at the operating frequency, or a shorter dipole but calibrated to a half-wave dipole. When measurements are performed above 4 GHz, a horn radiator must be used. For measurements between 1 GHz and 4 GHz, either a horn radiator or a half-wave dipole may be used. The center of this antenna must coincide with the reference point of the test sample. This reference point must be the center of the sample when its antenna is mounted inside the housing, or the point where the external antenna is connected to the housing.

The distance between the bottom end of the dipole and the ground surface must not be less than 0.3 m.

The substitute antenna must be connected to a calibrated signal transmitter when the measurement position is used to measure spurious emissions and effective radiated power of the transmitter. The substitute antenna must be connected to a calibrated receiver measuring instrument when the measurement position is used to measure receiver sensitivity.

The signal generator and receiver must operate at the frequencies to be measured and must be connected to the antenna through appropriate balanced and matching circuits.

NOTE: The gain of a horn radiator is typically represented corresponding to an isotropic radiator.

C.1.4. Optional Indoor Measurement Position

When the signal frequency being measured exceeds 80 MHz, the measurement can be performed at an indoor measurement position. If this measurement position is used, it must be clearly noted in the test report.

The measurement position may be a laboratory with a minimum area of 6 m x 7 m and a minimum height of 2.7 m.

In addition to the measurement equipment and operator, the measurement room should be as open as possible to avoid reflective objects other than walls, ceiling, and floor.

Reflections from the wall behind the measured equipment must be reduced by placing a metal absorber panel in front of the wall. For horizontal polarization measurements, corner reflectors placed around the receiver measurement antenna are used to reduce the reflection effect from the opposite wall and ceiling, floor. Similarly, for vertical polarization measurements, corner reflectors are used to reduce the reflection effect from side walls. At lower frequencies (below approximately 175 MHz), corner reflectors or absorber panels are not necessary. For experimental reasons, a half-wave dipole antenna may be replaced by a constant-length antenna, such that its length is within the range of λ/4 to λ at the measurement frequency and with a sufficiently sensitive measurement system. By the same measurement method, the half-wavelength distance to the top can be changed.

The measurement antenna, receiver measuring instrument, substitute antenna, and calibrated signal generator are used in the same manner as in the standard method.

To prevent errors due to near-field phase cancellation effects between the direct signal and remaining reflected signals, the substitute antenna must be moved by ±0.1 mm in the direction of the measurement antenna as well as in two directions perpendicular to the initial direction.

If changes in distance cause the signal level to change by more than 2 dB, the test sample must be repositioned until the signal level change drops below 2 dB.

Figure C.2 - Indoor Measurement Position Layout

C.2. Guidance on Using Radiation Measurement Positions

For measurements related to the use of radiation fields, positions according to the requirements of Section C.1 may be used. When using such measurement positions, the following conditions must be monitored to ensure the stability of the measurement results.

C.2.1. Measurement Distance

Experimental measurements show that the measurement distance is not a decisive condition and does not significantly affect the measurement results provided that this distance is not less than λ/2 at the measurement frequency and with attention to the annexes herein. Typically, measurement rooms use distances of 3 m, 5 m, 10 m, and 30 m.

C.2.2. Measurement Antenna

Different types of measurement antennas can be used because performing alternative measurements reduces error effects in the measurement results.

Changing the height of the measurement antenna between 1 m and 4 m is a necessary condition to find the maximum radiation point.

For frequencies below about 100 MHz, changing the height mentioned above is unnecessary.

C.2.3. Substitute Antenna

When using different types of substitute antennas below about 80 MHz, the measurement results may differ.

When using short dipole receiving antennas at these frequencies, details about the antenna type must accompany the measurement results. Attention must be paid to calibration factors when using short dipole receiving antennas.

C.2.4. Dummy Antenna

In radiation measurements, the size of the dummy antenna must be smaller than the measured sample.

Where possible, the dummy antenna should be directly connected to the measured sample.

In cases where connecting cables are needed, care must be taken to minimize radiation from the cable, for example, by using ferrite cores or double-shielded cables.

C.2.5. Coaxial Cable

The position of auxiliary cables (for example power cables, microphone cables, etc.) when not separated may affect the measurement results. To obtain reusable results, auxiliary cables and wires must be arranged vertically from top to bottom (through a hole in the insulating support).

C.2.6. BNo. tr"b) In addition to the lists of public services issued according to the provisions of Clause 2, Article 4 of this Decree, specialized agencies under provincial People's Committees shall report to the provincial People's Committee for decision-making on amending, supplementing, or issuing the list of public services funded by the state budget within their jurisdiction and consistent with the local budget capacity within the approved budget by the Provincial People's Assembly, and send it to the Ministry of Finance and relevant ministries and sectors for supervision during implementation." sound measurement

When performing sound measurements with the maximum available sensitivity (radiation) of the receiver, the sound output must be controlled by connecting the sound signal from the speaker to the microphone. In radiation measurement, all conductive materials must be placed on the ground and the sound signal is transmitted from the transmitter to the test microphone through a non-conductive acoustic tube.

The acoustic tube must have an appropriate length. The acoustic tube must have an internal diameter of 6 mm and a thickness of 1.5 mm. A plastic funnel with a diameter corresponding to the speaker of the transmitter must be attached directly in front of the speaker. The plastic funnel must ensure flexibility at the point where it connects to the transmitter to avoid mechanical resonance. The small end of the funnel must be connected to one end of the acoustic tube and the microphone to the other end.

C.3. Additional indoor measurement positions using a non-reflective chamber (optional)

For radiation measurements, when the frequency of the measured signal exceeds 30 MHz, the measurement can be performed in an indoor measurement position using a well-shielded non-reflective chamber that simulates free space conditions. If such a chamber is used, it must be clearly stated in the measurement report.

The measurement antenna, receiver, substitute antenna, and calibrated signal generator are used similarly to the common methods described in section C.1. For the frequency range of 30 MHz to 100 MHz, additional calibration adjustments are required.

An example of this measurement position could be a non-reflective measurement chamber with dimensions of 10 m x 5 m x 5 m.

The walls and ceiling need to be covered with a high-frequency absorber layer of 1 meter thick.

The measurement floor needs to be covered with a 1-meter-thick metal absorber layer and the wooden floor must be able to bear the weight of the measuring equipment and operator.

For measurements up to 127.75 GHz, a distance of 3 meters to 5 meters along the vertical axis between the measurement rooms can be used. The structure of this type of room is described below.

C.3.1. Example of the structure of a non-reflective measurement chamber

Free-space field measurements can be simulated in a shielded chamber where the walls are covered with high-frequency absorbers. Figure C.3 shows the shielding attenuation and return loss requirements of the walls in such a measurement room. Since the size and properties of typical absorber materials are critical factors below 100 MHz (absorber layer height <1 m, reflection reduction <20 dB), such a room is usually more suitable for measurements above 100 MHz. Figure C.4 shows the structure of a non-reflective shielded measurement chamber with a floor area of 5 m x 10 m and a height of 5 m.

The ceiling and walls are covered with conical high-frequency absorbers approximately 1 meter high. The floor is covered with an absorber layer.

The inner dimensions of the room are 3 m x 8 m x 3 m, allowing for a maximum measurement distance of 5 meters along the center axis.

At 100 MHz, the measurement distance can be increased to a maximum of 2λ.

The floor absorber layer reduces reflections, thus eliminating the need to change antenna height and considering floor reflection impact requirements.

Therefore, the measurement results can be verified by simple calculations while minimizing measurement instability due to the simplified measurement configuration.

C.3.2. Parasitic Reflection Effects in Non-Reflective Measurement Chambers

For wave propagation in free space under far-field conditions, the correlation coefficient E = E₀ (R₀/R) is an appropriate factor representing the dependence of the electric field intensity E on the distance R, where E₀ is the reference field strength at the reference distance R₀.

This correlation coefficient is effectively used in comparative measurements because all constants are eliminated through cable ratios and losses, asymmetrical antenna connections, or antenna sizes are irrelevant.

Deviations from the ideal curve can be easily observed if the equation is logarithmically plotted because the ideal correlation between field strength and distance is a straight line, and experimental deviations can be clearly seen. Indirect methods show parasitic interference caused by reflections more easily and clearly than reflection loss measurements.

With a non-reflective measurement chamber of the size given in section C.3 at low frequencies below 100 MHz, there are no far-field conditions, and therefore stronger reflections require careful correction. For the medium frequency range from 100 MHz to 1 GHz, the dependence of field strength on distance follows theoretical predictions accurately.

From 1 GHz to 12.75 GHz, the dependence of field strength on distance will not correlate precisely due to significant reflection effects.

C.3.3. Calibration of Non-Reflective Measurement Chambers

Calibration of non-reflective measurement chambers must be carried out within the frequency range of 30 MHz to 12.75 GHz.

Figure C.3 - Technical Requirements for Shielding and Reflection

Floor surface

Figure C.4 - Example of the Structure of a Non-Reflective Measurement Chamber

Appendix D

Product Name, Goods According to QCVN

HS code for VHF telephone equipment used for marine mobile services

Bibliography

[1] ETSI EN 300 162-1 V1.4.1 (2006-05): Electromagnetic Compatibility and Radio Spectrum Matters (ERM); Radiotelephone Transmitters and Receivers for the Maritime Mobile Service Operating in VHF Bands; Part 1: Technical Characteristics and Methods of Measurement.

[2] ETSI EN 300 162-2 V1.2.1 (2006-12): Electromagnetic Compatibility and Radio Spectrum Matters (ERM); Radiotelephone Transmitters and Receivers for the Maritime Mobile Service Operating in VHF Bands; Part 2: Harmonized EN Covering Essential Requirements of Article 3.2 of the R&TTE Directive.

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. Symbols

1.6. Abbreviations

Chapter 2. TECHNICAL PROVISIONS

2.1. General requirements

2.1.1. Structure

2.1.2. Control and indication requirements

2.1.3. Handset and speaker combination

2.1.4. Safety measures

2.1.5. Labeling

2.1.6. Equipment Startup

2.2. Technical Requirements

2.2.1. Channel Switching Time

2.2.2. Modulation and Radiation Characteristics Classification

2.2.3. Multi-watch Features

2.2.4. DSC Control Interface

2.3. General Test Conditions

2.3.1. Arrangement of Test Signals for Receiver Input

2.3.2. Mute function

2.3.3. Normal measurement modulation

2.3.4. Dummy antenna

2.3.5. Arrangement for feeding measurement signals to the transmitter input

2.3.6. Measurement channels

2.3.7. Measurement uncertainty and explanation of measurement results

2.3.8. Measurement conditions, power supply, and temperature

2.3.9. Normal measurement conditions

2.3.10. Extreme measurement conditions

2.3.11. Procedure for measuring at extreme temperatures

2.4. Environmental tests

2.4.1. Procedure

2.4.2. Quality Testing

2.4.3. Vibration Test

2.4.4. Temperature Test

2.5. Requirements for Transmitters

2.5.1. Frequency Error

2.5.2. Carrier Power

2.5.3. Frequency Deviation

2.5.4. Microphone Sensitivity Including Microphone

2.5.5. Audio Frequency Response

2.5.6. Distortion of the audio frequency emission

2.5.7. Adjacent Channel Power

2.5.8. Conducted false emissions to the antenna

2.5.9. Shell radiation and other conducted false emissions different from conducted false emissions to the antenna

2.5.10. Modulation Overload of the Transmitter

2.5.11. Low-Frequency Input Characteristics of DSC

2.5.12. Audio Input Limitation of DSC

2.5.13. Modulation Start Time

2.5.14. Transmitter Frequency Jump

2.6. Requirements for receivers

2.6.1. Rated audio frequency output power and harmonic distortion

2.6.2. Audio frequency response

||| 2.6.3.1. Definition

||| Feed two input signals to the receiver through a combining network (see 2.3.1). The desired signal is a normally modulated signal (see 2.3.3). The undesired signal is modulated at 400 Hz with a frequency deviation of ±3 kHz. Both input signals are at the receiver's rated frequency to be tested. Repeat the measurement with the undesired signal shifted ±3 kHz.

||| Repeat the measurement under limit test conditions (apply simultaneously 2.3.10.1 and 2.3.10.2) with the level of the desired signal set to the value corresponding to the maximum usable sensitivity also under these conditions.

2.6.6.1. Definition

2.6.7. Intermodulation Response

2.6.8. Blocking Characteristics

2.6.9. Spurious Emission Leakage

2.6.10. Spurious Radiation Emissions

2.6.11. Receiver Noise

2.6.12. Audio Mute Function

2.6.13. Audio Mute Delay

2.6.14. Multiple Observation Characteristics

The DSC audio characteristic is the level of two DSC tones at the DSC audio output terminals when the receiver is receiving an accurately modulated DSC signal.

2.7.1. Receiver sensitivity reduction due to simultaneous reception and transmission

The reduction in receiver sensitivity is caused by power transfer from the transmitter to the receiver due to coupling effects.

2.7.2. Internal mixing in duplex transmitter-receiver

3. MANAGEMENT PROVISIONS

4. RESPONSIBILITIES OF ORGANIZATIONS AND INDIVIDUALS

Chapter 5. ORGANIZATION OF IMPLEMENTATION

Appendix A (Provisions) Measurement Receiver for Channel Adjacent Power Measurement

Appendix B (Regulation) Protocol for IEC 1162-1 Frequency Setup Information Orders

Appendix C (Regulation) Radiation Measurements

Appendix D (Regulation) HS Code for VHF Mobile Maritime Communication Equipment

Bibliography