SJ 20566-1996 Measurement methods for electrical performance of low frequency/very low frequency transmitters

SJ 20566-1996 Low frequency/very low frequency transmitter electrical performance measurement method SJ20566-1996 standard download decompression password: www.bzxz.net

Military Standard of the Electronic Industry of the People's Republic of China FL5820
SJ20566-96
Methods of measurement of
eletrical performance for LF/VLF 1996-08-30 Issued
1997-01-01 Implemented
Ministry of Electronics Industry of the People's Republic of China
1.1 Subject matter
1.2 Scope of application
2 Reference documents
3 Definitions
3.1 Rated output power
3.2 Frequency stability
3.3 Frequency error
3.4 ​​Sound-off voltage
3.5 Harmonic level
3.6 Transmitter voltage
3.7 In-band noise
3.8 Extra-band noise
3.9 Input power
3.10 Overall efficiency
Keying rate
4 General requirements
4.1 Standard test conditions
4.2 Supplementary test conditions 5.1 Rated output power measurement method 5.2 Frequency stability measurement method 5.3 Frequency error measurement method 5.4 Acoustic and electrical measurement method 5.5 Harmonic level measurement method 5.6 Harmonic level measurement method 5.7 In-band noise measurement method 5.8 Out-band noise measurement method 5.9 Input power measurement method 5.10 Total efficiency measurement method 5.11 Keying rate measurement method Appendix A Main measuring instruments and their recommended characteristics (reference parts) TIKAONKA-
People's Republic of China Electronics Industry Military Standard Low frequency/very low frequency transmitter electrical performance measurement method 1 Scope
1.1 Subject
SJ20566-96
This standard specifies the definition, measurement items and measurement methods of electrical performance of low frequency/very low frequency communication transmitters (hereinafter referred to as transmitters).
1.2 Applicable scope
This standard applies to the measurement of electrical performance of sub-low frequency/base low frequency communication transmitters (without antenna). Specific measurement items and performance indicators shall be specified in accordance with product specifications.
For special transmitters, the definition and measurement methods of electrical performance items not specified in this standard shall be determined by the supply and demand parties through consultation.
2 References
GB2421—89 General Rules for Basic Environmental Tests for Electrical and Electronic Products 3 Definitions
3.1 Rated output power ratedoutputpower The average power supplied to the measuring load in one RF cycle when the transmitter is modulated in accordance with the prescribed method and the measuring load is connected to the output terminal without any modulated carrier, expressed as a ratio (W). 3.2 Frequency stability The ratio of half of the maximum frequency change value of the transmitter within the prescribed duration after the prescribed warm-up time under the standard test conditions to the nominal frequency,
Note: The term frequency stability depends on the duration of operation and measurement. If the duration is one day, it is called daily frequency stability; if the duration is one month, it is called monthly frequency stability.
3.3 Frequency error frequencyerror
The difference between the unmodulated carrier frequency and the assigned carrier frequency (the assigned carrier frequency is any of the nominal carrier frequencies, expressed in Hz), or the ratio of the error value to the assigned carrier frequency, expressed in 10-. 3.4 Hum level
The periodic noise generated by the parasitic modulation of the power supply on the signal is called hum. The frequency of these periodic noises is equal to the fundamental frequency of the AC power supply voltage and its harmonic frequencies. Issued by the Ministry of Electronics Industry of the People's Republic of China on August 30, 1996 and implemented on January 1, 1997
SI 20566-96
The transmitter is adjusted according to the prescribed method in the absence of any modulated carrier to achieve the rated output power. The ratio of the power of the maximum sound component to the rated output power is defined as the machine's harmonic level, expressed in decibels (dB). 3.5 Harmonic level harmonic level
The transmitter is adjusted according to the prescribed method to achieve the rated output power without adding any modulated carrier. The ratio of any maximum component to the rated output power at the frequency point that is an integer multiple of the carrier frequency is expressed in decibels (dB). 3.6 Parasitic level
Parasitic emission is an electromagnetic emission caused by unwanted oscillations in the transmitter circuit. It is neither a component of the information signal nor a harmonic of the carrier. The ratio of the largest component to the rated output power is defined as the parasitic level of the machine, expressed in decibels (dB).
3.7 In-band noise
The ratio of the maximum average component of the continuous noise spectrum emitted by the transmitter and falling within the specified frequency band to the rated output power, expressed in decibels per hertz (dB/Hz).
3.8 Out-band noise out-band noise
The ratio of the maximum average component of the continuous noise spectrum emitted by the transmitter and falling outside the specified frequency band to the rated output power, expressed in decibels per Hz (dB/Hz).
3.9 Input powerinputpower
The active power transmitted to the transmitter when the transmitter outputs rated power with any modulated carrier, including the power absorbed by the auxiliary equipment required for the normal operation of the transmitter. Expressed in watts (W). 3.10 Overall efficiencyoverall efficiencyThe ratio of the rated output power of the transmitter to the total input active power without any modulated carrier, expressed in percentage (%).
3.11 Keying ratekeying rate
When keying telegraph, under the specified waveform distortion conditions, the transmission rate that can be achieved is expressed in baud (Bd). 4 General requirements
4.1 Standard test conditions
Unless otherwise specified, the measurements shall be carried out under the following standard test conditions. 4.1.1 Standard atmospheric conditions
The standard atmospheric conditions shall comply with the provisions of GB2421. 4.1.1.1 Reference standard atmospheric conditions
If the law of the measured parameter changing with temperature and air pressure is known, the basic parameter value shall be measured under the standard atmospheric conditions of the test specified in Article 4.1.1.3 of this standard. If necessary, it can be corrected to the parameter value under the following reference standard atmospheric conditions by calculation:
Temperature: 20℃:
Air pressure: 101.3kPa.
Note: Since relative humidity cannot be corrected by calculation, it is not specified. 4.1.1.2 Standard atmospheric conditions for referee test If the law of variation of the measured parameter with temperature, pressure and humidity is unknown, one of the standard atmospheric conditions for referee test listed in Table 1 shall be selected by agreement for measurement. When the measured temperature is not 20°C or other values ​​specified in the relevant standards, the appropriate limit values ​​of specific parameters may be determined by agreement between the supplier and the buyer.
SI20566-96
Note: If the relative sensitivity has no effect on the test results, it may be ignored. Table 1
Nominal
Low tolerance
4.1.1.3 Standard atmospheric conditions for test
Wide tolerance
The range of standard atmospheric conditions for measurement and test is shown in Table 2. Narrow range
15 ~35
Relative condensation
Relative humidity
Wide range
60~ 70
86 ~106
86~106
86-106
When measurements cannot be made under the standard atmospheric conditions of the test, the actual conditions shall be stated in the test report. In a series of measurements on a given device, the temperature and relative humidity shall be approximately constant as part of the entire test.
4.1.2 Standard power supply conditions
The voltage and frequency of the power supply are measured at the power input terminal when the transmitter is working. If the transmitter is connected to non-detachable wires and cables, it can be measured at the power input plug, but the type, cross-sectional shape and length of the wires and cables should be recorded. Standard power supply conditions are divided into DC power supply and AC power supply. 4.1.2.1 Standard test voltage of DC power supply The standard test voltage of DC power supply is based on the total nominal voltage, and its error should be within ±2%, and the ripple should be less than 2%. 4.1.2.2 Standard test voltage and frequency of AC power supply When there is no special provision, the standard test voltage is 220, 380V, and its error should be within 2%. The standard test frequency is 50Hz. Its error should be within ±2%, and the harmonic distortion coefficient should be less than 5%. 4.2 Supplementary test conditions
4.2.1 Connection of measuring equipment
The connection should be carefully made to ensure that the measuring equipment and any combined device will not have an adverse effect on the load conditions of the transmitter. 4.2.2 Measuring equipment and requirements
The accuracy of the measuring instrument should ensure the accuracy requirements of the measured indicators. For example, the frequency accuracy of the instrument and equipment related to the measurement error must be one order of magnitude higher. For individual projects, it is necessary to select the measuring instrument appropriately to prevent the instrument from introducing additional errors. The main performance of some general measuring instruments recommended by this standard is shown in Appendix A (reference). 4.2.3 Measuring load and its requirements
The load used in the electrical performance measurement is called the measuring load. Its reactance part depends on the specific situation, and the resistance part is generally not greater than 80A
4.2.4 Measurement workplace conditions
SJ20566-96
The measurement workplace should be clean, and there should be no gas, salt mist and strong sunlight radiation that damages the equipment. There should be measures to isolate industrial interference, spark interference and atmospheric interference. Obvious mechanical vibration and impact should be avoided. 5 Detailed requirements
5.1 Rated output power measurement method
5.1.1 Heat-mechanical equivalent method
One of the following methods can be used
5.1.1.1 The power (sometimes the liquid itself) cooled by water (or other liquids) is used as the power consumption element of the measured load to convert high-frequency energy into heat. The average power consumed can be calculated using formula (1): P=qr
Where: p——average power, W:
mass density of cooling liquid, k/1 (mass density of water is 1): p
c—specific heat capacity of cooling liquid, j/kg, C (specific heat capacity of water is 4187); 9—flow rate of cooling liquid, 1/s:
A——temperature rise of cooling liquid, ℃.
++（1）
Note: To prevent errors caused by heat radiation and convection loss, At is kept as low as possible, as long as the thermometer indicates sufficient accuracy. The thermometers at the upstream and outlet should be placed near the resistors. 5.1.1.2 The resistor cooled by water evaporation is used as the power consumption element of the measuring load. The average power consumed under standard atmospheric pressure can be calculated using formula (2):
p=4187gm(A+539).....
Where: p——average power, W;
um flow rate of steaming water after cooling, kg/s; △t——temperature difference between boiling point 100℃ and cooled water, C; .2)
Note: D The measuring load should have a complete water and steam separation device to prevent the steam from carrying unvaporized water droplets and causing large errors. If a deep water-cooled condenser is used, the temperature difference and flow rate of the secondary water can be measured, and then the formula of the water-cooled resistor measurement method can be used for calculation. At this time, the water droplets that have not been vaporized will not cause the temperature difference. ? Because the flow rate of the distilled water after condensation is unstable, the temperature difference indication of the induction effect fluctuates, and the reading can be taken as the average value. 5.1.1.3 Using the air-cooled resistor as the power consumption element of the load measurement, under standard atmospheric pressure, the average power consumed can be calculated using formula (3):
+ = 3484At/(t + 273)..
Where: power - average power, W;
—air flow rate, L/s;
A—temperature difference before and after air cooling, t;
temperature before air cooling, t.
When the wind speed is difficult to measure accurately, a DC or frequency power supply can be used to heat the resistor and the reading can be taken using the comparison method, but the cooling wind speed should be kept constant.
5.1.2 RF voltmeter method
a, the measurement block diagram is shown in Figure 1:
ITKAONKAca-
Low frequency signal
Aisheng type
SJ2056696bzxZ.net
transmitter
h. The transmitter is adjusted according to the specified method without any modulated carrier: c. Calculate the average power according to formula (4):
V——effective value of RF voltage meter, V:
R——capacitive resistance of measurement load, 2
5.2 Frequency stability measurement method
5.2.1 Direct counting method
Net. The measurement block diagram is shown in Figure 2:
transmitter
measurement
frequency counter
b. When the transmitter is not modulated by any carrier, adjust the machine according to the prescribed method. After it reaches the prescribed warm-up time, use a counting frequency meter to directly measure the carrier frequency value. Note: It is best to add an error multiplier during measurement to reduce the measurement error. 5.2.2 Oscilloscope method
a. The measurement block diagram is shown in Figure 3;
transmitter
period combiner
oscilloscope
b. When the transmitter is not modulated by any carrier, adjust the machine according to the prescribed method. After it reaches the prescribed warm-up time, add the measured carrier frequency signal to the oscilloscope Y axis, and add the standard frequency source output signal to the oscilloscope external synchronization input terminal. The measured frequency and the standard frequency should be the same. At this time, the oscilloscope displays a cycle of sine wave; c. Use a stopwatch to record the number of cycles of the waveform moving within a unit time, and calculate it according to formula (5): Af = N/T...
Where: Af—measured frequency change value, Hz: SJ 20566-96
The number of waveform cycles moving within a T time;
TMeasurement time, se
Note: ① For transmitters with higher indicators, it is better to use the oscilloscope method, and pay attention to the direction of waveform movement in order to judge the positive and negative deviations. 5.3 Frequency error measurement method
a, the measurement method is shown in 5.2;
h. In the entire frequency range of the transmitter, select at least three frequency points, repeat step a, and take the largest frequency change value, which is the frequency error of the machine. 5.4 Hum level measurement method
a, the measurement block diagram is shown in Figure 4:
Emitting system
Yang slider
h. Under the condition that no modulated carrier is added, the transmitter is adjusted according to the prescribed method so that the output power reaches the rated power; c. Set the center of the spectrum analyzer to the carrier frequency, the sweep width to 1800Hz, the filter bandwidth to 3Hz, and the output power of the carrier frequency to dB:
d. Measure the largest hum component, which is the hum level. 5.5 Harmonic level measurement method
a, the measurement block diagram is shown in Figure 4:
b. Under the condition that no modulated carrier is added, the transmitter is adjusted according to the prescribed method so that the output power reaches the rated power; c. The sweep range of the spectrum analyzer is [0kHz to 1MHz/7.5MHz (low frequency/low frequency), the filter bandwidth is set to 3001Iz, and the output power of the carrier frequency is set to 0dB; d. Measure the largest harmonic component, which is the harmonic level under this carrier frequency; e. In the whole frequency range of the transmitter, select at least three frequency points, repeat steps b, c, d, and take the maximum harmonic level value, which is the harmonic level of the machine. 5.6 Parasitic current measurement method
The measurement diagram is shown in Figure 4:
1. The transmitter is adjusted according to the prescribed method without any modulated carrier, so that the output power reaches the rated power; the scanning range of the spectrum analyzer is 10kI[z to 1MIIz/7.5MHz (base low frequency/low frequency), the filter bandwidth is set to c.
300Hz, and the output power of the carrier frequency is set to 0dB: d. Measure the maximum parasitic level, which is the parasitic level: e. In the whole frequency range of the transmitter, select at least three frequency points, repeat steps b, c, d, and take the maximum parasitic level value, which is the parasitic level of the machine. 5.7 Internal Media Acoustic Measurement Method
a The measurement block diagram is shown in Figure 4:
b The transmitter is adjusted according to the prescribed method without adding any modulated carrier, so that the output power reaches the rated power; e. The center of the frequency harmonic analyzer is the carrier frequency f, and the sweep range is f. -200Hz to f, +200Hz,Set the filter bandwidth to 3Hz and the load output power to 0dB: HTTKAONTKAca-
SI 20566 96
d. Measure the average value of the maximum component of the continuous noise spectrum from f. -120Hz to f. +120Hz, and add -10g3 to obtain the in-band media noise. (If there is a \dB/Hz\ selection button on the spectrum analyzer, this function button can be used to read directly); e. Select at least three frequency points within the entire frequency range of the transmitter, repeat steps b, c, and d, and take the maximum in-band noise value, which is the in-band noise of the machine. Note: If it is difficult to measure the whole machine, it can be measured at the output end of the exciter. 5.8 Out-of-band noise measurement method
a: The measurement block diagram is shown in Figure 4;
h. Under the condition of no modulated carrier, the transmitter is adjusted according to the prescribed method to make the output power reach the rated power; the frequency sweep range of the spectrum analyzer is 10Hz to 500kHz/1MHz (very low frequency/low frequency), the filter bandwidth is set to 100Hz, and the output power of the carrier frequency is set to 0dB; d. Measure the average value of the maximum component of the continuous noise spectrum in the frequency band outside ±500z, plus 10g100, which is the out-of-band noise (if there is an \IB/Hz\ selection button on the spectrum analyzer, this function button can be used to read it directly) e. In the entire frequency range of the transmitter, select at least three frequency points, repeat steps b, c, and d, and take the largest out-of-band noise, which is the out-of-band noise of the machine. Note: If the whole machine has difficulty in measuring, it can be measured at the output end of the exciter. 5.9 Input power measurement method
a, the measurement block diagram is shown in Figure 5;
Power meter
Transmitter
Couple
b, the transmitter is adjusted according to the specified method without adding any modulated carrier, so that the output power reaches the rated power. 5.9.1 DC power supply measurement method
Use a DC voltmeter and an ammeter to measure the voltage and current value of the power supply, and the product is the input active power. 5.9.2 AC power supply measurement method
5.9.2.1 Use a single-phase power supply
Use a power meter to measure the input active power.
5.9.2.2 Use a three-phase power supply
Use a power meter to measure the input active power of each phase separately, and then calculate the sum of the three phases. 5.10 Total efficiency measurement method
Use 5.1 to measure the rated output power:
b. Use 5 and 9 to measure the total input active power; divide the result of step a by the result of step b to get the total efficiency: c,
d, in the entire frequency range of the transmitter, select at least 10 frequency points, repeat steps a, b, and c, and take the minimum value, which is the total efficiency of the transmitter.
Note: 5.9 and 5.10 need to be measured at the same time. 5.11 Keying rate measurement method
5.11.1 Amplitude keying rate
Measurement block diagram is shown in Figure 6:
Jiaofa 1
SI 20566 96
b. Without any modulated carrier, adjust the transmitter according to the prescribed method so that the output power reaches the rated power; c. Select the working mode of the function generator in the square wave state with a duty cycle of 1:1, and make the square wave rate equal to the baud number required by the transmitter product specification:
The transmitter should work normally, and the output envelope waveform observed on the oscilloscope should meet the requirements. d.
5.11.2 Frequency Shift Keying Rate
Without any modulated carrier, adjust the transmitter according to the prescribed method so that the output power reaches the rated power; b. Select the working mode in the frequency shift state, and set the shift value and baud number according to the requirements of the transmitter product specification; The transmitter should work normally, the message is correct, and the transmission distortion should meet the requirements. Appendix A Main measuring instruments and their recommended characteristics (reference) Recommended instruments and their characteristics can be selected for measurement according to the measurement method described in this standard. Low frequency signal generator a. Frequency range: 1~500kHz; b. Frequency characteristics: ±1.5dB c. Output waveform nonlinear distortion: less than 1% d. Output maximum amplitude: more than 3V. A2 Counting frequency meter (with external error multiplier) a. Frequency range: 50Hz~-500kHz b. Input impedance: greater than 1MO, capacitance not greater than 25pF C. Crystal stability and error are better than the measured index - an order of magnitude. A3 Dual-channel oscilloscope
a. Frequency range: 10Hz~100MHz;
b. Probe input impedance: 10M0=10%, capacitance less than 25pF.A4 RF voltmeter
a. Frequency range: 20Hz~500kHz;
b, AC voltage: 0--3000V;
Measurement error: 5~300kH2, less than 3%;
d. Input impedance: greater than 50ko.
45 Spectrum analyzer
Frequency range: 0~-110MHz;
b, Maximum input level: 10dBm;
Input impedance: 502;
It is best to use HP4195A, HP3585A.
A6 function generator
Frequency range 10~160kHz:
b, modulation frequency: 10～150kl[z;
c. Modulation mode: 1:1 square wave frequency shift (frequency shift value =10~=75Hz): d, output amplitude: ≥3VepEP)e
Additional instructions:
SI 20566 96
This standard is under the jurisdiction of China Electronics Standardization Institute. This standard was drafted by the State Council. The main drafters of this standard are Yang Bin and Wang Wenqi. Project code: B33014.
TYKAONT KAca-1 The measurement block diagram of amplitude keying rate
is shown in Figure 6:
Jiaofa 1
SI 20566 96
b. When the transmitter is not modulated by any carrier, adjust the machine according to the prescribed method so that the output power reaches the rated power; c. Select the working mode of the function generator to the square wave state with a duty cycle of 1:1, and make the square wave rate equal to the baud number required by the transmitter product specification:
The transmitter should work normally, and the output envelope waveform observed on the oscilloscope should meet the requirements. d.
5.11.2 Frequency shift keying rate
When the transmitter is not modulated by any carrier, adjust the machine according to the prescribed method so that the output power reaches the rated power; b. Select the working mode to be in the frequency shift state, and set the shift value and baud number according to the requirements of the transmitter product specification; The transmitter should work normally, the message is correct, and the transmission distortion should meet the requirements. Appendix A Main measuring instruments and their recommended characteristics (reference) Recommended instruments and their characteristics can be selected for measurement according to the measurement method described in this standard. Low frequency signal generator a. Frequency range: 1~500kHz; b. Frequency characteristics: ±1.5dB c. Output waveform nonlinear distortion: less than 1% d. Output maximum amplitude: more than 3V. A2 Counting frequency meter (with external error multiplier) a. Frequency range: 50Hz~-500kHz b. Input impedance: greater than 1MO, capacitance not greater than 25pF C. Crystal stability and error are better than the measured index - an order of magnitude. A3 Dual-channel oscilloscope
a. Frequency range: 10Hz~100MHz;
b. Probe input impedance: 10M0=10%, capacitance less than 25pF.A4 RF voltmeter
a. Frequency range: 20Hz~500kHz;
b, AC voltage: 0--3000V;
Measurement error: 5~300kH2, less than 3%;
d. Input impedance: greater than 50ko.
45 Spectrum analyzer
Frequency range: 0~-110MHz;
b, Maximum input level: 10dBm;
Input impedance: 502;
It is best to use HP4195A, HP3585A.
A6 function generator
Frequency range 10~160kHz:
b, modulation frequency: 10～150kl[z;
c. Modulation mode: 1:1 square wave frequency shift (frequency shift value =10~=75Hz): d, output amplitude: ≥3VepEP)e
Additional instructions:
SI 20566 96
This standard is under the jurisdiction of China Electronics Standardization Institute. This standard was drafted by the State Council. The main drafters of this standard are Yang Bin and Wang Wenqi. Project code: B33014.
TYKAONT KAca-1 The measurement block diagram of amplitude keying rate
is shown in Figure 6:
Jiaofa 1
SI 20566 96
b. When the transmitter is not modulated by any carrier, adjust the machine according to the prescribed method so that the output power reaches the rated power; c. Select the working mode of the function generator to the square wave state with a duty cycle of 1:1, and make the square wave rate equal to the baud number required by the transmitter product specification:
The transmitter should work normally, and the output envelope waveform observed on the oscilloscope should meet the requirements. d.
5.11.2 Frequency shift keying rate
When the transmitter is not modulated by any carrier, adjust the machine according to the prescribed method so that the output power reaches the rated power; b. Select the working mode to be in the frequency shift state, and set the shift value and baud number according to the requirements of the transmitter product specification; The transmitter should work normally, the message is correct, and the transmission distortion should meet the requirements. Appendix A Main measuring instruments and their recommended characteristics (reference) Recommended instruments and their characteristics can be selected for measurement according to the measurement method described in this standard. Low frequency signal generator a. Frequency range: 1~500kHz; b. Frequency characteristics: ±1.5dB c. Output waveform nonlinear distortion: less than 1% d. Output maximum amplitude: more than 3V. A2 Counting frequency meter (with external error multiplier) a. Frequency range: 50Hz~-500kHz b. Input impedance: greater than 1MO, capacitance not greater than 25pF C. Crystal stability and error are better than the measured index - an order of magnitude. A3 Dual-channel oscilloscope
a. Frequency range: 10Hz~100MHz;
b. Probe input impedance: 10M0=10%, capacitance less than 25pF.A4 RF voltmeter
a. Frequency range: 20Hz~500kHz;
b, AC voltage: 0--3000V;
Measurement error: 5~300kH2, less than 3%;
d. Input impedance: greater than 50ko.
45 Spectrum analyzer
Frequency range: 0~-110MHz;
b, Maximum input level: 10dBm;
Input impedance: 502;
It is best to use HP4195A, HP3585A.
A6 function generator
Frequency range 10~160kHz:
b, modulation frequency: 10～150kl[z;
c. Modulation mode: 1:1 square wave frequency shift (frequency shift value =10~=75Hz): d, output amplitude: ≥3VepEP)e
Additional instructions:
SI 20566 96
This standard is under the jurisdiction of China Electronics Standardization Institute. This standard was drafted by the State Council. The main drafters of this standard are Yang Bin and Wang Wenqi. Project code: B33014.
TYKAONT KAca-
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