GB 4859-1984 Basic measurement methods for anti-interference characteristics of electrical equipment
Some standard content:
National Standard of the People's Republic of China
General methods of measurementof inmunlty to interference
for electrical equipment
This standard is the basic measurement method of inmunlty to interference characteristics of electrical equipment. This standard applies to:
a. Measuring the electromagnetic sensitivity of electrical equipment. UDC 621.3 : 621
GB 4859-84
b. Assessing whether the inmunlty to interference performance of electrical equipment meets the electromagnetic sensitivity limit value specified in the product technical conditions. Under the premise of meeting the requirements of this standard, various types of electrical equipment can formulate corresponding inmunlty to interference characteristic measurement methods and specify the test items that need to be carried out.
1 Terms and units
1.1 Terms and terms
The terms and terms used in this standard meet the requirements of the national standard GB4365-84 "Terms and terms for electromagnetic interference below the line". The following terms and definitions apply to this standard:
1.1.1 Sensitive test signal: simulated interference signal applied to the test object when conducting sensitivity measurement. 1.1.2 Sensitive field: magnetic field, electric field or electromagnetic field emitted by special equipment or transmitting antenna when conducting radiated sensitivity measurement. 1.2 Units
The unit names and symbols used in this standard shall comply with the relevant provisions of GB3100-82 "International System of Units and Its Application". The unit names and symbols in Table 1 shall apply to this standard. Table 1 Unit Names and Symbols
Name of Unit
Magnetic Flux Density
Decibel (Picowatt)
Decibel (Microvolt)
Decibel (Microampere)
Decibel (Picoampere)
General Requirements for Measurement
dn (pw)
dB (μV)
dE (μA)
dB（pT)
National Bureau of Standards 1984-12:29 Issued
Benchmark value
Base name
Magnetic field strength
Electric field
Decibel (microampere/meter)
Decibel (ampere/meter)
Decibel (microvolt/meter)
Decibel (meter)
dB(μA/m）
dB(Aim)
dB(μV/m)
dB(V/m)
lμa/m
1985-10 -01 Implementation
2.1 Working state
GB4859—84
The test product shall be measured under the normal working conditions specified in the product technical requirements. 2.2 Working frequency
During the measurement, the working frequency of the test product shall be determined according to the following principles: 2.2.1 If the test product has only one continuously adjustable frequency band or only one fixed channel range, two working frequencies shall be selected in the frequency band or channel so that they are no more than 5% away from the upper and lower limits of the frequency band or channel range. If the ratio of the selected frequencies is greater than 2, the center frequency of the frequency band or channel range shall also be used as the working frequency. 2.2.2 If the test product has more than 100 continuously adjustable frequency bands or fixed channel ranges, one working frequency shall be selected in each frequency band or channel range so that they are 5% away from the two ends of the frequency band or channel range. 2.2.3 If the test product has more than 6 continuously adjustable frequency bands or fixed channel ranges, the center frequency of each frequency band or channel range shall be used as its working frequency.
2.2.4 In addition to the operating frequencies selected according to the above principles, other operating frequencies specified in the product technical conditions may also be included. 2.8 Test frequency
When measuring, the frequency of the sensitive test signal or the inductive field shall be captured within the range specified in the product technical conditions. In each octave, the chamber shall select at least one most sensitive frequency point. In addition, measurements may also be made at the test frequency specified in the product technical conditions (such as power supply frequency and its harmonic frequencies, local oscillation frequency, intermediate frequency, etc.). 2.4 Grounding plate
When the test piece needs to be placed on a gold grounding plate for measurement, the front of the test piece shall be 100±20mm away from the edge of the grounding plate. The grounding plate shall overlap the shell of the shielding chamber (see Figure 24). The distance between two adjacent overlapping points shall be less than 900mm, and the DC overlapping resistance shall be less than 2.5m2. The length-to-width ratio of the overlapping copper strip shall not exceed 5 to 1. The requirements for the grounding half plate are as follows: 8. Material and thickness: copper plate with a thickness of not less than 0.25mm, or brass plate with a thickness of not less than 0.63mm, or aluminum plate with a thickness of not less than 1.5mm.
b. Area: The area occupied by the bottom surface of the test piece is less than 0.5m2, but at least 2.25m2. c. Width: at least 760mm.
2.5 Test site
2.5.1 The conducted inductance measurement should be carried out in a shielded room. 2.5.2 When measuring the conducted sensitivity of the test piece, the test piece, working performance monitoring equipment, etc. should avoid being affected by the electromagnetic energy emitted by the signal source, and the power supply of the test piece should be separated from the power supply of other test equipment. 2.5.3 The radiation sensitivity measurement shall be carried out in the area specified by the radiation sensitivity measurement method. In the test area, except for the necessary equipment such as the signal source, transmitting antenna, and test product, the other test equipment and items not related to the test shall be placed outside the test area, and irrelevant test personnel shall also leave the test area.
2.6 Arrangement of test products
2.6.1 When the test product needs to be placed on a metal grounding plate for measurement, the power line, signal line, control line and other cables shall be arranged as follows:
a. Inside the grounding plate and 100±20mm from the edge. b. 50mm higher than the grounding plate.
2.6.2 During the measurement, the test product shall simulate the actual installation and use conditions, and shall be overlapped or grounded according to the provisions of the product technical conditions. For example, the outer frame, base and other components of the test product shall be overlapped together, or all overlapped on the grounding plate. If the test product has an external grounding terminal, it shall be connected to the grounding half plate.
Part 1 Conducted Sensitivity Measurement Method
330Hz~50kHz. Power Line Conducted Sensitivity Measurement 3.1 Purpose
GB4859--84
Used to determine the sensitivity of the test product to the conducted interference from the power line. 3.2 Test Equipment
3.2.1 Signal Source: Low-frequency power signal generator or a combination of a low-frequency signal generator and a power amplifier, which should be able to provide sufficient output power:
3.2.2 Measuring Instrument: A calibrated oscilloscope or a frequency-selective electric meter. The input impedance of the frequency-selective electric meter is required to be greater than F6002. 3.2.3 Capacitor: The capacitance is 100μF. 3.2.4 Isolation transformer: When the working current of the test product flows through the secondary winding of the isolation transformer, the positive drop produced on the winding should be less than 10% of the rated working voltage of the test product, and the iron core should not be saturated. When the secondary winding is short-circuited, the leakage inductance of the primary winding is not more than 0.8uH. Its output impedance after connecting to the signal source shall meet the requirements of Article 3.5. 3.2.5 Equipment for monitoring the working performance of the test product. Power cord
No. 1 wine
Monitoring service
Figure 130Hz~5ukHz DC power line conducted sensitivity measurement Camp number tracking
Positive current Power line
Research
Equipment to be tested
Figure 230Hz～50kHz AC power line conducted inductance measurement Note: (The simulated load should simulate the input impedance of the AC power supply end of the test product, and its value and properties are specified in the product technical conditions. ②"" indicates the same-name terminal of the isolation transformer. 3.3 Measurement steps
3.8.1 Conducted sensitivity measurement
3.3.1.1 Connect the test product and the test equipment in Figure 1 or 2. 3.3.1.2 Adjust the signal source to increase its output level step by step, and find the most sensitive frequency within the specified test frequency range according to the requirements of Article 2.3. point, and monitor the working condition of the test product at the same time until the test product performance declines, fails or the parameter deviation exceeds the allowable value specified in the product technical conditions. Record the type of fault and the corresponding sensitivity. 3.4 Anti-interference performance assessment
GB4859—B4
When assessing the anti-interference performance of the test product, you can choose one of the following two methods according to the provisions of the product technical conditions. 3.4.1 Use the measurement method specified in this standard to measure the electromagnetic sensitivity of the test product. If the measured electromagnetic sensitivity is higher than the electromagnetic sensitivity limit value specified in the product technical conditions, it is considered that the anti-interference performance of the test product meets the specified requirements. 3.4.2 According to the measurement method specified in this standard, according to the conducted sensitivity limit value specified in the product technical conditions, the corresponding sensitive test signal shall be injected into the test product, or the test product shall be placed in a sensitive field corresponding to the radiated sensitivity limit value in the product technical conditions. Monitor the working condition of the test product, and judge whether the anti-F interference performance of the test product meets the requirements of the product technical conditions based on the monitoring results. 3.5 Output impedance of signal source
When the primary winding of the isolation transformer is connected to the signal source, the output impedance of the signal source seen from both ends of the secondary winding of the isolation transformer should not be greater than 0.59, and shall be measured according to the following method. 3.5.1 Adjust the output level of the signal source to a certain value, and measure the voltage Vee at both ends of the secondary winding of the isolation transformer. 3.5.2 Connect a resistor R with a resistance value not greater than 10S2 to both ends of the secondary winding of the isolation transformer, and measure the voltage Vee at both ends of the resistor R.
3.5.3 The output impedance of the signal source is calculated as follows: 2=
Wherein: B - the output impedance of the signal source, 0, R, (a.-V)
K - the resistor connected in parallel at both ends of the secondary winding of the isolation transformer, 2.. - the voltage measured by 3.5.1, VVc - the voltage measured by 3.5.2, V. ..+
3.5.4 The output impedance of the signal source should be measured at least at 30Hz, 300H1z, 3kHz, 30kHz, and 50kHz. 3.5.5 If the measured impedance B is greater than 0.52, then the turns ratio of the isolation transformer winding needs to be adjusted, or a resistor needs to be connected at both ends of the secondary winding until the impedance meets the specified requirements. 450kHz~100MHz Power Line Conducted Susceptibility Measurement 4.1 Purpose
To determine the sensitivity of the test product to the conducted interference from the power line. 4.2 Test Equipment
4.2.1 Signal Source: RF power signal generator or a combination of RF signal generator and power amplifier. Its output impedance is 502 and has sufficient output power.
4.2.2 Measuring Instrument: Calibrated Oscilloscope, High Input Impedance Voltmeter, Interference Measuring Instrument, etc. 4.2.3 Artificial Power Network: For the general form, network parameters, impedance characteristics, etc. of the power network, see GR3907-83 "Basic Measurement Methods for Industrial Element Line Interference".
4.2.4 Signal and Note Network: See Figure 3.
4.2.5 Equipment for monitoring the performance of the test product. (A)
Note: ① The resistance of the non-inductive resistor is 70.7. GB 4859—84
Figure 3 Signal injection network
Note: The resistance of the non-inductive resistor r is 86.62. ②Terminal A is connected to a measuring instrument with an input impedance of 50%. ③Terminal B is connected to an artificial power supply network.
@Terminal C is connected to a signal source with an output impedance of 502. The voltage at terminal B is equal to the reading of the measuring instrument plus 10.7dB. 4.3 Test steps
4.3.1 Conducted sensitivity measurement
4.3.1.1 Connect the test product and the test equipment according to Figure 4. ②Terminal A is connected to a measuring instrument with a high input impedance. (8B terminal is connected to the artificial power grid.
①C terminal is connected to the signal source with an output impedance of 502.③The voltage at terminal B! E is equal to the reading of the measuring instrument. 4.3.1.2 If the test object is placed on a metal grounding plate for measurement, the shell of the artificial power grid should be overlapped with the grounding half plate, and the overlap point should be as close as possible to the overlap point between the test object and the grounding plate. 4.3.1.3 When the output impedance of the signal source and the input impedance of the measuring instrument are both 502, the signal injection network of Figure 3 (A) is used. If the measuring instrument has a high input impedance, the signal injection network of Figure 3 (B) is used. 4.3.1.4 Adjust the signal source so that its output level is gradually increased, and then Within the specified test frequency range, find the most sensitive frequency point according to the requirements of Article 2.3, and monitor the working condition of the test product at the same time until the performance of the test product degrades, fails, or the parameter deviation exceeds the allowable value specified in the product technical conditions. Record the type of fault and the corresponding sensitivity. 4.4 Anti-interference performance assessment
When assessing the anti-interference performance of the test product, it can be carried out according to the provisions of Article 3.4. 4.5 Modulation method
According to the provisions of the relevant standards and technical documents of the product, the inductive test signal or the inductive field shall be modulated. If there is no such provision, it can be modulated in the following manner.
4.5.1 Test product with audio channel. ||t t||AM receiver: modulation frequency is 1000Hz, modulation index is 30%. FM receiver: modulation frequency is 1000Hz, frequency deviation is 10kHz. b.
Single sideband receiver: no modulation is required.
Other equipment: same as AM receiver.
4.5.2 For the test products with video channel (except receiver): modulate with pulse signal, modulation index is 90~100%, pulse width is 2/BW, repetition frequency is BW/1000, where BW is the visual bandwidth (Hz).
4.5.3 Digital equipment
Working performance
Route European equipment
. Signal source
GB4859—84
Electric network
Partial test note
Skynet, etc.
Measurement of Shenzhen Han
Figure 150kIIz-100MHz power line conducted sensitivity measurement When pulse modulation is used, the pulse width and repetition frequency are the same as the pulse used by the test object itself. 4.5.4 Non-resonant equipment
The modulation frequency is 1000Hz and the modulation index is 30%. 5 Power line repetitive spike pulse conducted sensitivity measurement 5.1 Purpose
The purpose is to determine the sensitivity of the test object to repetitive spike pulses from AC and DC power lines. 5.2 Spike pulse waveform
If the product technical conditions do not specify the spike pulse waveform, the waveform shown in Figure 5 can be used. 5.3 Test equipment
5.3.1 Pulse generator: The output impedance of it combined with the isolation transformer should be less than 0.59, and it can output the required voltage on a resistor with a resistance of 0.5Ω. When connected in parallel (Figure 7), a spike pulse generator with high output impedance can also be used, requiring it to output the required voltage on a resistor with a resistance of 52Ω. 5.3.2 Capacitor: A through-hole capacitor with a capacitance of 10μF. 5.3.3 Oscilloscope: Any oscilloscope with a bandwidth of 10MHz and a suitable scanning speed. Inductor: An air-core inductor with an inductance of 20μH should be allowed to pass the required working current of the test product. 5.3.4
Isolation transformer: See 3.2.4.
Power isolation transformer: The transformation ratio is 1:1. 5.3.7
Equipment for monitoring the performance of the test product.
5.4 Measurement Arrangement
5.4.1 For the AC power line of the test product, the series injection method shown in Figure 6 is generally used. For the DC power line of the test product, the injection method shown in Figures 6 and 7 is generally used. 5.4.2
5.4.3 For a test unit with a grounded metal shell, the insertion method shown in Figure 8 is used. 5.5 Measurement Steps
5.5.1 Conducted Sensitivity Measurement
5.5.1.1 Connect the test equipment to the test equipment according to the requirements of Section 5.4. 5.5.1.2 Inject positive and negative repetitive sharp pulses into the test product according to the following three conditions. The pulse amplitude starts from zero and increases successively. Measure the conducted sensitivity of the test product.
And. b. Inject a short spike pulse with a repetition frequency of 6 to 10 times/5 into the power line of the test product in accordance with the waveform requirements of Article 5.2. b. Inject a repetitive spike pulse synchronized with the power frequency into the power line of the test product, and adjust the trigger phase of the spike pulse to find the trigger phase that is most sensitive to the repetitive spike pulse. GB4859-84
c. Inject a repetitive spike pulse into the power line of the test product under other operating conditions that may be sensitive to repetitive spike pulses. 5.5.1.3 Simultaneously monitor the working conditions of the test product in each of the above cases until the performance of the test product degrades, fails, or the parameter deviation exceeds the allowable value specified in the product technical conditions. Note the type of fault and the corresponding sensitivity. 5.6 Anti-interference performance assessment
When assessing the anti-interference performance of the test product, it can be carried out in accordance with the provisions of Article 3.4. E
fr--ius
t,uμs
Vertical complex sharp pulse waveform
Null current or south
current power line
G=tμFwww.bzxz.net
Dust gland non
Stop
50(μs)
Working energy
Figure 6 Power line repeated dust pulse conduction sensitivity measurement (series injection) C1oμF
And current line
L - 2uμH
Class-pulse
Generator
Oscilloscope
Working place
Monitoring equipment
Figure 7 Power line repetitive spike pulse conducted sensitivity measurement (parallel connection) Intense pulse
Single-pole double-pole
GB4859—84
Weak isolator
Current testing equipment
Oscilloscope
Figure 8 Power line repetitive spike pulse non-conducted sensitivity measurement (asymmetric injection) Note: When the test product is powered by a DC power supply, the power isolation transformer is moved to the power line of the monitor. 6 Ground line injection conducted sensitivity measurement (10kHz～50kHz) 6.1 Self-determination! The sensitivity of the test product with a grounded metal shell to the conducted interference appearing on the common ground impedance. 6.2 Test equipment
6.2.1 Signal source: Power signal generator or combination of signal generator and power amplifier, which should be able to provide sufficient output power. 6.2.2 Measuring instrument: A certified indicator or high-input impedance voltmeter. 6.2.3 Isolation transformer: 3.2.4
6.2.4 Equipment for monitoring performance of test 1
6.3 Measurement steps
6.3.1 Conductive sensitivity flammability measurement
6.3.1.1 Connect the test equipment according to Figure 9. The test equipment should be isolated from the cell. The shell of the test product should be grounded through the secondary winding of the isolation transformer.
6.3.1.2 Adjust the signal source, increase its output level gradually, find the most sensitive frequency point within the specified test frequency range according to the requirements of 2.3, and monitor the working condition of the test product until the performance of the test product decreases, fails or the parameter deviation exceeds the allowable value specified in the product technical conditions, and record the type of fault and the corresponding sensitivity. 6.4 Anti-interference performance assessment
When assessing the anti-interference performance of the test product, it can be carried out according to the provisions of 3.4. Dual-to-dual
Working number
To transformer
Working performance monitoring
Figure 9 Conducted sensitivity measurement (10kHz~50klz) GB 4859-84
7 Radio frequency current conducted sensitivity measurement (10kHz~30MHz) 7.1 Purpose
To determine the sensitivity of the test product to the radio frequency current of its metal shell and the connecting cable shielding layer. 7.2 Test equipment
7.2.1 Signal source, RF power signal generator or the combination of RF signal generator and power amplifier, shall be able to provide sufficient RF current.
Neutralizing transformer: The inductance of each winding is 1mH. 7.2.2
Resistor, non-inductive resistor with a resistance of 110, its accuracy shall not be less than ±5%. Measuring instrument: high input impedance RF voltage meter, current probe, down-interference meter. Equipment used to monitor the working performance of the test product.
7.3 Measurement steps
Conducted sensitivity measurement
The test product and test equipment are connected according to Figure 10 (A) and Figure 11 (A) or Figure 10 (B) and Figure 11 (B). 7.3.1.1
1.3.1.2 Adjust the signal source so that its output level increases gradually. Find the most sensitive frequency point within the specified test frequency range according to the requirements of Article 2.3, and monitor the operation of the test product at the same time until the performance of the test product degrades, fails, or the parameter deviation exceeds the allowable value specified in the product technical conditions. Record the type of fault and the corresponding sensitivity. 7.3.1.3 During measurement, the RF current should pass from the - corner to all other corners of the metal shell of the test product in sequence. For shielded cables, the RF current should pass through the shielding layer of the screened cable. .4 Anti-interference performance assessment
When assessing the anti-jamming performance of the test product, it can be carried out in accordance with the provisions of Article 3.4. .5 Modulation mode
When it is required to modulate the sensitive test signal, it can be carried out in accordance with the provisions of Article 4.5. 1? Source
Signal source
Transformer
Transformer
Tester
Constant pressure meter
Figure 10 RF current is injected into the metal casing of the test sample (10kH2~30MHz) Signal source
GB4859-84
Transformer
Transformer
Current manipulator
1 Performance
Monitoring equipment
Testing equipment
Figure 11 RF current is injected into the cable screen layer (10kHz~30MHz) Note: "T" in the figure actually marks the device or equipment connected to the test sample. 8.2.1 Signal source: Two signal sources should be able to provide the output voltage required for measurement and cover the required test frequency. Three-way network: It is required to provide more than 20dB isolation between the two signal generators, and one signal path should maintain an impedance of 8. 2.2
Matching, and at the same time, it is required that it does not generate modulation itself: 8.2.3 Low-pass filter: Two. After the signal source output signal passes through the low-pass filter, its harmonic level should be at least 80dB lower than the fundamental wave. 8.2.4 Frequency counter: The frequency measurement accuracy should reach 10-6. 8.2.5 Step attenuator.
8.2.6 Coaxial switch.
8.2.7 Equipment for monitoring the receiver output.
8.3 Measurement steps
8.3.1 The receiver under test and the test equipment are as follows 8.3.2 Set the output of signal generator 1 to zero, tune signal generator T to the tuning frequency of the receiver under test according to the provisions of Article 2.2, and modulate it according to the provisions of Article 8.4, adjust its output level, so that the output level of the receiver under test reaches the standard value specified in Article 8.5, record the input level V and frequency f of signal generator I, set the output of signal generator to zero, repeat the above steps for signal generator II, and record its output voltage Vzc.
Tube number
Signal
GB 485984
Lake filter
Three-way circuit
Tidal filter
Attenuator
Figure 12 Two-signal independent modulation suppression measurement
Sex makeup machine
Note: When measuring, the automatic gain control in the receiver and the automatic frequency control circuit should be turned off and not work. 8.3.3 Make the output of signal generator II zero, and modulate signal generator 1 according to the provisions of 8.4. Adjust its output level so that it is equal to the sum of the modulation suppression test level specified in the technical conditions of the receiver and the level V obtained in 8.3.2, and keep this output level unchanged. Then, gradually increase the frequency of the signal generator until the test receiver has no modulation. Note the frequency distortion and keep it at or below 8.3.2. 8.3.4 Set the output of signal generator I to zero, signal generator II to no modulation, and adjust its frequency to f+Af-f,+24" (where, = -f.), and observe the first-order modulation. Set the output levels of signal generators 1 and 1 to be equal to the sum of the intermodulation rejection ratio specified in the technical conditions of the receiver and the level V specified in 8.3.2. If the receiver under test has no obvious response at this time, then gradually increase the output levels of the two signal generators until the receiver under test shows a response. Keep this output level unchanged, and fine-tune the frequency of signal generator I to maximize the response of the receiver under test. Note the frequency of signal generator II and keep it unchanged. 8.3.5 Set the output of signal generator 1 to zero. If the response of the receiver under test still exists, it means that the response is not caused by intermodulation. If the response disappears, it means that the response is caused by intermodulation. 8.3.6 If the inspection result according to 8.3.5 indicates that the response in 8.3.4 is caused by intermodulation, then reduce the input of the two signal generators by the same amount until the output level of the receiver under test reaches the standard response value. At this time, record the output levels V and V2 of the two signal generators, and calculate the modulation suppression level according to the following formula: Sin-V.
Formula Si
m-order intermodulation suppression level, dB:
Sim =V--V
Output 8.3.The output voltage of signal generator T and II obtained in item 6, dB (μV); the output level of signal generator T and II obtained in item 8.3.2, dB (μV). (2)
Vic,[20-
8.3.7 Adjust the frequencies of signal generators T and II to f. -Af5fm-2△1 respectively, and repeat the steps of items 8.3.3 to 8.3.6.
A If the third-order intermodulation has been observed, the fifth-order intermodulation does not need to be observed. 8.3.8 Observe the order intermodulation in the same way, so that the frequency of signal generator II is successively f. Then it is not observed, and the fifth-order intermodulation is no longer required. 8.4 Modulation mode
If the technical conditions of the receiver under test stipulate the modulation mode of the signal generator: then the following modulation modes can be used: 1: AM receiver: Use a 400H stop string to perform 30% modulation. b. Single sideband receiver and FM receiver, no modulation is required. GB 4859—84
℃. Pulse receiver: Use pulse modulation to make 80% of the pulse spectrum energy concentrated in the 3d band of the receiver. 8.5 Standard output level of the receiver
The standard output level of the receiver shall strictly comply with the provisions on sensitivity measurement in the technical conditions of the receiver. If no provisions are made in the technical conditions, the following output level can be used, where S is the signal level and N is the noise level of the receiver. 8.5.1 AM receiver, single sideband receiver, pulse receiver: SN/N: 1odB.
8.5.2 FM receiver:
a. No modulation
Noise level: 10dB.
b. "Modulation
SN/N:10dB
9 Receiver input false signal response suppression measurement (30I12～10GJIz) 9.1 Purpose
The false signal at the receiver input will cause interference to the receiver. This test method is used to determine the receiver's sensitivity to this interference. 9.2 Test equipment
Same as 8.2.
9.3 Measurement steps
9.3.1 Connect the test equipment to the receiver under test as shown in Figure 12. 9.3.2 Make the output of the signal generator port zero. Tune signal generator 1 to the tuning frequency fe of the receiver under test as specified in Article 2.2, and modulate it as specified in Article 8.4, and then adjust its output level so that the output voltage of the receiver under test reaches the standard value specified in Article 8.5. Note the output voltage and frequency of signal generator I, make the output of signal generator I zero, repeat the above steps for signal generator II, and note its output voltage V. 9.3.3 Modulate signal generator I as specified in Article 8.4, and adjust its output level to the voltage obtained in Article 9.3.2. Level V10. Signal generator II is not reverse modulated, and its output level is adjusted to be equal to the sum of the false signal response suppression level specified in the receiver technical conditions and the voltage 2n obtained in Article 9.3.2.
9.3.4 If the receiver has no obvious response when signal generator II is scanned within the test frequency range specified in Article 9.4, the output level of signal generator II should be increased and the frequency scan should be repeated until the receiver under test shows a false signal response. Then, at the frequency point where the response occurs, reduce the output voltage of signal generator II until the false signal response drops to the allowable value specified in the receiver technical conditions, record the input level of signal generator II and calculate the false signal response suppression voltage Ss according to the following formula: =-
--false signal response suppression level, dB;
--the output level of the signal generator II obtained by 9.3.4, dB (uV);--the output level of the signal generator II obtained by 9.3.2, dB (μV) 9.4 Test frequency range
(4)
9.4.1 For the receiver, the signal generator is scanned within the frequency range specified in Table 2. The lower limit frequency is the lowest value in column A, and the upper limit frequency is the highest value in column B (should not exceed 10GHz). This test is not performed between the two frequency points with a decrease of 80dB in the receiver selection curve.
Table 2 Test frequency range
5fmttF
or 20f,
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