GB/T 3907-1983 Basic measurement methods for industrial radio interference
Some standard content:
National Standard of the People's Republic of China
General methods of measurementfor industrial radio interference
This standard applies to the following industrial interference sources that cause interference to radio reception: a: motors, low-voltage electrical and electronic equipment; b, industrial, scientific and medical equipment;
motor vehicles and other ignition devices;
d. Radio and television receivers,
e, household appliances, electric tools and similar appliances. This standard applies to the frequency range of 10kHz to 1000MHz. UDC 621.396: 621
.391.82: 621
GB 3907 -
This standard is mainly formulated with reference to the 16th publication of the International Special Committee on Radio Interference (CISPR) "Specifications for Radio Interference Measurement Equipment and Measurement Methods". 1 Terms and units
1.1 The radio interference terms used in this standard are mainly based on the relevant provisions of the International Electric Dictionary (IEV902). The following terms apply to this standard.
1.1.1 Continuous interference
Interference caused by pulsed or chaotic noise or overlapping noise of the two, with a duration of more than 200ms. 1.1.2 Intermittent interference
Interference that is not continuous.
1.1.3 Countable clicks
Clicks that exceed the allowable value of continuous interference. 1.1.4 Click rate
The number of countable clicks per minute.
1.2 The measurement units used in this standard are as follows: The unit of interference voltage is microvolt (μV), when expressed in decibel, 1uV is odB; the unit of interference current is microampere (μA), when expressed in decibel, 1μA is odB; the unit of interference field strength is microvolt/meter (μV/m), when expressed in decibel, 1uV/m is odB; the unit of interference power is picowatt (pW), when expressed in decibel, 1pW is odB. 2 Measuring instruments
2.1 Basic performance of interference measuring instrument
This standard adopts the interference measuring instrument with quasi-peak detection, and the basic performance is listed in Table 1. 2.2 Non-quasi-peak measuring instrument
When the measurement results of the non-quasi-peak instrument can be converted into the equivalent measurement value of the quasi-peak instrument, the non-quasi-peak measuring instrument is allowed to be used. Issued by the National Bureau of Standards in 1983-1031
Implemented in 198410-01bzxz.net
Performance requirements
Bandwidth at 6dB
Detector charging time band
Detector discharge time constant
Critical Yang Ni time meter head mechanical time constant
Circuit overload factor before detector
Circuit overload factor after detector
3 General measurement conditions
3.1 Environmental interference
GB 3907-83
10～150 kHz
0. 15 ~ 30 MHtz
30 -- 1000MFtz
Before the test product is connected to the measurement circuit but not powered on, the interference voltage caused by the environment indicated on the interference measuring instrument should be at least 20dB lower than the allowable value of the interference voltage of the test product; the interference field strength caused by environmental radiation should be at least 10dB lower than the allowable value of the interference field strength of the test product.
If the allowable values of the interference voltage and interference field strength are not specified for the test product, the interference caused by the environment indicated on the interference measuring instrument should be at least 20dB and 10dB lower than the interference value of the test product, respectively. 3.2 Environmental conditions
Carry out wireless test indoors When measuring electrical interference, the following environmental conditions shall be met: ambient air temperature 10~40℃, relative humidity not more than 85%. When measuring outdoors, the environmental conditions shall comply with the use conditions specified in professional standards and measuring instrument standards, but measurements are not allowed in humid environments, away from the sun or with condensation. When there is a special need, the environmental conditions should be indicated. 3.3 Measurement frequency
3.3.1 For broadband radio interference, measure at the priority frequencies listed in Table 2. When there is external interference H on the measurement frequency, deviation from the frequency measurement is allowed. The frequency deviation is shown in Table 2. Table 2
Frequency band
10 ～150kHz
0.15~30MHz
30~300MHz
300 -~ 1000MHz
Measurement frequency
10，15，,25，35，55，100，1500.16,0.24,0.55,1.0,1.4,2.0,3.5,6.0,10,22.3030，45，65，90，150，180，220，300300,400,500,600,800,1000
GB 3907-83
3.3.2 For narrowband radio interference, the fundamental and harmonic frequencies shall be measured. 3.3.3 Whether it is broadband or narrowband interference, a frequency sweep check shall be performed over the entire measurement frequency band when necessary. 3.3.4 The radio interference generated by switching action shall be measured at the following frequencies: 10kHz, 160kHz, 550kHz, 1400kHz, 10MHz, 45MHz, 90MHz, 220MHz. If the measurement time is very long, it is allowed to measure at one of the following frequencies: 10kHz, 160kHz, 45MHz.
3.4 Observation time
When measuring continuous interference, the observation time for each measurement shall be at least 155. If the pointer swings greatly, the observation time needs to be appropriately extended. 3.4.1
When measuring intermittent interference, the observation time is calculated based on 40 countable clicks, or the time required to count 40 switch actions accordingly. 3.4.2
But the maximum time does not exceed 2hc
3.5 Test product operation conditions
3.5.1 The test product shall be operated in the state specified by the professional standards, and the measurement shall be carried out when it is in a stable state. Test products with multiple working conditions shall be measured under various specified working conditions, and the test results shall be based on the maximum value measured at each frequency. 3.5.2 If the product can work in either grounded or ungrounded state, the interference measurement shall be carried out in both grounded and ungrounded states. The measurement results shall be based on the maximum value measured at each frequency. 4 Conducted interference voltage measurement
4.1 Artificial power supply network
4.1.1 Unless otherwise specified, the interference voltage measurement shall be based on an artificial power supply network. 4.1.2 Artificial power supply networks usually have the following forms: 10~150kHz artificial power supply network. The network adopts 50S2, 50uH parallel impedance form, circuit parameters and impedance characteristics are shown in Appendix A.
0.15~30MHz artificial power supply network. There are three different impedance forms of artificial power supply networks in this frequency band, and the parameters and impedance characteristics of each network are shown in Appendix A
4.2 Measurement layout
4.2.1 When measuring conducted interference voltage, the measurement layout is shown in Figure 1. When measuring interference at the power supply end of the test product, the artificial power supply network connection is shown in the solid line in the figure; when measuring interference at the load end of the test product, the artificial power supply network connection is shown in the energy line in the figure.
Mechanical load
or prime mover
Filtered
power
artificial
power network
4.2.2 The distance between the test sample and the artificial power network is 80cm1
underground
interference measuring instrument
power network
grounding plate
GB3907—83
4.2.3 The interference measuring instrument and the artificial power network are connected by a coaxial cable. 4.3 Interference voltage measurement
4.3.1 Interference voltage measurement of non-handheld, ungrounded test sample The test sample is placed on a non-metallic bracket 40cm high above a 2m×2m grounding plate. The distance between the test sample and any other grounding plane is at least 80cm. The test sample and the network are connected by a wire not longer than 1m. For test items with non-detachable flexible cables or cords, when the length of the cable or cord exceeds 80 cm, the excess length should be folded into a bundle of 30 to 40 cm. See Figure 2 for the measurement arrangement. 80 cm
Grounding test record
Analyzer
! Power supply network
4.3.2 Handheld, ungrounded test item interference voltage measurement Figure 2
Grounding sub-plate
Ungrounded test item
Grounding plate
First press 4.3.1. Perform interference voltage test, then connect the simulated hand for auxiliary test. The simulated hand consists of a metal foil wrapped in an insulating shell 1 and a resistor and capacitor element in series. The width of the metal foil is 6cm. The capacitance is 200pf and the resistance is 500%2. The capacitor element end is connected to the metal foil, and the resistor element end is connected to the grounding plate. 4.3.3 Interference voltage measurement of grounded test piece
The test piece is connected to the artificial power network with a wire length equal to or less than 1m. The test piece housing is connected to the network housing with a ground wire of phase length. The power line and the ground wire should be laid in parallel, with a spacing of less than 10cm between them. The measurement arrangement is shown in Figure 2. 4.3.4 Symmetrical interference voltage measurement of the test piece
When a line-powered test piece needs to perform symmetrical interference voltage measurement, the measurement frequency is limited to less than 1605kHz. In order to avoid affecting the impedance of the network terminal, the interference measuring instrument is connected to the artificial power network through a balancing transformer, and its input impedance is not less than 10002. The impedance of the A-type network used for symmetrical interference measurement is 1502. The connection between the network and the test object is shown in Figure 3. The P terminal is connected to the test object. > 500 μH
>500μH
Balancing transformer
+interference tester
4.3.5 Intermittent interference voltage measurement
GB3907--83
The intermittent interference voltage measurement of the switch action product is shown in Figure 2. Measurement method! Continuous interference voltage measurement is the same. The interference analyzer records the instantaneous interference amplitude and click rate. The measurement of interference duration can also be carried out according to the provisions of Article 4.4. 4.3.6 Line network interference voltage measurement
When measuring the interference voltage of the power supply line network, the connection should be arranged according to Figure 4. The input end of the interference tester should be connected with an isolation capacitor C and a resistor R. Then it is connected to the line network under test. The interference voltage is calculated as follows: 1500
Formula f interference voltage, μV;
U-+ interference measuring instrument indication voltage, uV;
R-interference measuring instrument input impedance, $. Power supply network
X≤1500s2
4.4 Interference duration measurement
150092 -- R)
When measuring oxygen intermittent interference, the interference duration must be measured to determine whether it is a click interference. The measurement of interference duration is arranged according to the arrangement of Pavilion 5. The interference signal taken out from the frequency output end of the interference measuring instrument is sent to the input end of the memory oscilloscope. The instantaneous waveform of the interference can be measured by adjusting the oscilloscope scanning speed and trigger level. The interference duration is read from the ruler on the oscilloscope. Power supply
5 Conducted interference current measurement
People! Power supply
Tester
Intermediate frequency output terminal
Wavelet filter
5.1 Scope of application
This method is used to measure high-frequency interference current transmitted along the conductor. The frequency ranges from 10kliz to 30MHz. 5.2 Basic performance requirements of current probe
The insertion impedance is less than 0.5;
b. The transfer impedance is greater than 12;
GB3907--83
When the conductor carries the following current, the magnetic circuit of the probe should not be saturated: c.
DC is less than 300A, and AC is less than 100A. 5.3 Interference current measurement
5.3.1 The arrangement of interference current measurement is shown in Figure 6. The power supply needs to be isolated from the test piece through a 10uf feedthrough capacitor. The casing of the feedthrough and capacitor should be connected to the grounding plate. If the test piece is grounded, its casing should be electrically connected to the grounding plate. The measured wire should be 10cm above the grounding plate, and the length of the wire from the test sample to the capacitor should not exceed 1m. 2
Capacitor
Load line
Current clamp
Power supply soft cable or soft wire
Capacitor
Current clamp
Transformer
Hand-held interference measuring instrument
Grounding plate
5.3.2 When measuring the interference current of the power line, the phase line and neutral line of the power line should be connected to a 10μf through-hole capacitor respectively; the length of the phase line and neutral line is 30cm.
When measuring, slowly move the current probe along the 30cm long measured line segment of the phase line and neutral line, and read the maximum indicated value of the voltage from the interference measuring instrument. The measured interference current value is obtained according to the following formula: I=UY
Formula?: "Interference current value, μA,
U is the maximum indicated voltage of the interference measuring instrument, μV; Y--the transfer admittance of the current probe, S.
5.3.3 When measuring the load line interference current, move the current probe slowly along the load wire and read the maximum indicated value of the voltage on the interference measuring instrument. The interference current value on the measured load line is obtained by the formula in Section 5.3.2. 6 Measurement of conducted interference power
6.1 Scope of application
This method is applicable to the measurement of interference power generated by power supply appliances in the 30-300MHz frequency band. This method can replace the radiated interference measurement of some appliances (such as household appliances and power tools). 6.2 Basic performance requirements of absorbing clamps
GB 3907-83
The impedance presented by the absorbing clamp to the tested product is 100～2502, and the reactance component is less than 20%. a.
b. The absorbing clamp can provide sufficient attenuation for external interference from the power grid. c. When the working current of the test crystal passes through, the magnetic circuit of the absorbing clamp should not be saturated. 6.3 Interference power measurement arrangement
6.3.1 The interference power measurement arrangement is shown in Figure 7. The test product must be placed on a non-metallic test bench with a distance of at least 40cm from other conductive objects or the ground.
Measured distance
and interference measuring instrument
Absorbing clamp
Interference analyzer
Filter
6.3.2 The tested power cord of the test product should be straightened and placed horizontally on the table. The power cord length L is calculated from the lowest test frequency: A max +!
武i: Amax
The wavelength corresponding to the lowest test frequency, m; 1—the length of the absorption clamp, m.
6.3.3 Pass the power line through the absorption clamp so that one side of the current transformer of the absorption clamp faces the direction of the test object and is close to the test object. 6.4 Continuous interference power measurement
(3)
6.4.1 Adjust the interference meter to the selected frequency and calibrate it. Turn on the power of the test object and put the test object in a stable working state. 6.4.2 Move the power absorption clamp steadily away from the direction of the test object. At each measuring frequency, repeatedly search for the position of the interference current antinode until the maximum reading appears on the indicator of the interference meter. 6.4.3 The interference power value of the test object is equal to the voltage indication value of the interference meter plus the correction value of the corresponding frequency on the correction curve of the absorption clamp, that is: P=U+K
武:p--i
Interference power of the test piece, dB;
U--Measured interference voltage, dB,
K-Correction value of the absorbing clamp, dB.
6.5 Measurement of intermittent interference power
(4)
6.5.1 In addition to the arrangement for continuous interference power measurement in accordance with 6.3, a continuous signal needs to be introduced to facilitate the search for the antinode position.
6.5.2 A battery-powered signal generator outputs a continuous signal. The signal is coupled to the power line of the test piece through a small inductor with stable performance and located near the test piece. By moving the position of the absorbing clamp, the antinode position at the maximum indication of the interference measuring instrument can be found. When measuring, fix the absorbing clamp at this position, and then remove the signal generator and the small inductor. Turn on the power supply of the test piece, and the intermittent F disturbance rate value of the test piece at this frequency can be measured. The calculation method is the same as that of 6.4.3. When changing the measurement frequency, the antinode position should be found again. 6.5.3 The interference analyzer and the interference measuring instrument are used together to measure the duration of intermittent interference and the click rate. 7 Radiated interference measurement
7.1 Site conditions
71.1 The test site should be an open, flat site without reflectors. Personnel and equipment not related to the measurement shall not enter the test site to avoid affecting the measurement results.
7.1.2 If the test site is an elliptical field, the test product and the interference measuring instrument antenna should be placed at the two foci of the ellipse respectively: the major axis of the ellipse is equal to 2 times the focal distance. The minor axis of the ellipse is equal to √3 times the focal distance. 1
7.2 Measurement layout
GB 3907--83
7.2.1 The layout of the test product and the connection with the power line refer to the provisions on interference voltage measurement in 4.2 and 4.3. 7.2.2 When measuring at close range, the artificial power network should not be placed between the test object and the antenna. The layout of the test object should be as close as possible to normal use.
7.3 Measurement antenna
7.3.110~150kHz frequency band
7.3.1.1. Magnetic field antenna
In this frequency band, the interference field is mainly the magnetic field component. To measure the magnetic field component, a shielded loop antenna is used. Alternatively, a suitable iron oxide magnetic rod antenna can be used.
7.3.1.2 Antenna balance
The antenna balance should be such that when the antenna rotates in a uniform electromagnetic field, the difference between the maximum indication and the minimum indication of the interference measuring instrument is not less than 20dB. 7.3.20.15~30MHz frequency band
7.3.2.1 Magnetic field antenna
When measuring the magnetic field component of interference in this frequency band, a shielded loop antenna is used. Its balance is the same as that of item 7.3.1.2. 7.3.2.2 Electric field antenna
When measuring the electric field component of interference, a symmetrical or asymmetrical antenna can be used. When using an asymmetrical antenna, the measurement result refers only to the electric field component that is effective for the whip antenna. The measurement result should indicate the type of antenna used. 7.3.330～300MHz frequency band
7.3.3.1 Electric field antenna
The antenna should be a symmetrical dipole antenna. When the frequency is higher than or equal to 80MHz, the length of the antenna should be the resonant length. When the frequency is lower than 80MHz, the antenna length can be the antenna length at 80MHz. Depending on the situation, broadband antennas and shortened dipole antennas are allowed.
The antenna is connected to the input end of the interference meter through a balanced-unbalanced transformer. The antenna should be arbitrarily selectable so that all polarization directions of the radio wave can be measured. The antenna height should be adjusted within 1～4m so that it can be fixed at the maximum measurement value position. 7.3.3.2 Antenna balance
When the dipole antenna rotates in a uniform electromagnetic field, the difference between the maximum indication and the minimum indication of the interference meter shall not be less than 20dB. 7.3.43001000MHz frequency band
7.3.4.1 Electric field antenna
When using a simple dipole antenna, the conditions are the same as those in 7.3.3.1. The balance of the antenna is the same as that in 7.3.3.2. 7.3.4.2 Complex antenna
Considering that the sensitivity of simple antennas is too low in this frequency band, complex antennas are allowed. Complex antennas include log-periodic antennas, helical antennas, etc.
Measurement distance
In order to conduct a comprehensive study of the test product, it is required to measure at several distances from the test product. The preferred distances are 1, 3, 10, 30, 100m, etc. In special cases, other distances can be selected. In all fields, the height of the antenna and the interference source will be indicated together with the measurement distance. 7.5 Field strength measurement procedure
7.5.1 Before measurement, the site environment should be checked and meet the requirements of Articles 3.1 and 7.1. 7.5.2 Arrange the test product and antenna according to the requirements of 7.2 and 7.3. 7.5.3 If the maximum radiation direction changes significantly with the test frequency, the maximum radiation direction should be measured at each frequency. 7.5.4 The maximum value measured is taken as the radiation interference value of the test product. 7.6 Interference field strength measurement at the use site
When measuring the interference field strength of the interference source at the use site, interference radiation measurements should be carried out in multiple directions to find the maximum value of the interference radiation under the actual use situation GB 390783
. It is not necessary to connect to the artificial power network during measurement. 7.7 Radiated interference power measurement
7.7.1 Scope of application
This method is applicable to the measurement of the radiated interference power generated by the internal battery-powered device in the frequency range of 30300MHz. 7.7.2 Site inspection
The measurement site should be flat and have no obvious uneven reflective surface. Whether the site is suitable is determined by the following method. Dipole A
Signal generator
Dipole B
Interference measuring instrument
According to Figure 8, take two dipole antennas and place them halfway and in parallel. The height h from the ground is 1.5m, and the distance s between them is 3m. Dipole antenna A is connected to the signal generator, and dipole antenna B is connected to the interference meter. During the inspection, tune the signal generator so that the interference meter has the maximum indication value, and adjust the signal generator so that it outputs a suitable level. When dipole antenna A moves 10 cm forward, backward, left and right, if the change in the indication value of the interference meter is no more than ±1.5 dB, the site is considered suitable.
Several frequency points should be selected within the entire measurement frequency band and the above measurements should be repeated. It is allowed to use a shortened dipole antenna or a broadband antenna for the above measurements. 7.7.3 Measurement arrangement
The test piece and the measuring antenna should be placed on a non-metallic bracket, both 1.5 m above the ground and about 3 m apart. The receiving antenna can be moved slightly to avoid being in the position of the minimum field strength synthesized by human radiation and reflection. The receiving antenna should be orthogonal to the plumb plane containing the center of the antenna and the center of the test piece, see Figure 9.
7.7.4 Measurement method
The test piece should be placed so that its largest size is in a horizontal position first. and then in a vertical position. For any position, the test piece must be rotated 360° in the water surface to obtain the maximum reading U on the measuring instrument. Note this U value. Remove the test piece from the measuring position and replace it with a horizontal dipole antenna A. The center position of antenna A should coincide with the original position of the test piece. Antenna A and antenna B should be placed parallel. Adjust the output of the signal generator so that the indication of the interference measuring instrument reaches the U value recorded above. At this time, the input power at the end of dipole antenna A is the interference power radiated by the test piece. Pole B
Tested product
Geometric center
8 Product sampling method and evaluation of measurement results 8.1 Sampling method
8.1.1 Sample conditions and batch composition
Interference measuring instrument
7777777777
8.1.1.1 The samples used for radio interference measurement should be products that meet all other requirements specified in product standards or technical conditions (except destructive tests).
GB 3907—83
8.1.1.2 The batch submitted for inspection may be composed of several small batches, but each batch submitted for inspection shall consist of products with the same model, similar structure, and roughly the same process conditions and production time. 8.1.2 Sampling
8.1.2.1 Samples shall be randomly selected from the batch submitted for inspection. Divide the entire batch of products into several small batches or parts according to a reasonable method, and then sample each batch or part in proportion to the percentage of each small batch or part in the entire batch. 8.1.2.2 The measurement of radio interference level is a type test item. For a certain model of mass-produced products, samples will be drawn according to one of the following methods:
day. For products that produce continuous interference, when a quantitative sampling test based on non-central t distribution is adopted, at least 5 samples shall be taken for each sampling. In special cases, 3 samples are allowed. b. For products that produce continuous interference, when a counting sampling test based on binomial distribution is adopted, at least 7 samples shall be taken for each sampling.
For simplicity, only... samples shall be taken for testing. c.
d. For products that produce intermittent interference, only one sample shall be taken for testing. 8.1.2.3 Samples must be randomly drawn from production for testing frequently or regularly, especially in the cases of items c and d above.
8.1.2.4 For products produced individually, each product shall be tested for radio interference level. 8.1.2.5 For a product that produces continuous interference, if there is a dispute over whether the test is qualified or not, the batch test can only be considered to be cancelled after appropriate sampling tests are carried out according to 8.1.2.2a and b. 8.1.2.6 For a product that produces intermittent interference, if there is a dispute over whether the test is qualified or not, the following shortened test procedure can be used, but it does not guarantee that the interference allowable value meets the statistical significance specified in 8.2.1. a. If the first sample is unqualified after inspection, then three more samples can be selected and tested at the frequency of the weekly sample or at the unqualified frequency point of the first sample.
b. The judgment conditions for whether the interference of the three additional samples is qualified or not are the same as those for the first sample. c. If all the three additional samples meet the requirements of 8.2.5, the type test is considered qualified. If one or more of the three additional samples do not meet the requirements of 8.2.5, the batch test can be cancelled. 8.2 Evaluation of interference level measurement results
8.2.1 The statistical significance of the specified interference level allowable values shall ensure that, with a confidence level of at least 80%, at least 80% of the tested batch of products have interference level values less than or equal to the specified interference allowable value, i.e., the 80%/80% criterion. 8.2.2 For a single product, within the specified measurement frequency band, all interference level values shall be less than or equal to the specified allowable value before it is judged to be qualified.
8.2.3 For products produced in large quantities, when taking 100 samples for testing, if the interference is of a continuous nature, the interference level shall be at least 2dB lower than the specified allowable value before the batch of products is judged to be qualified; if the interference is of an intermittent nature, it shall be tested according to 8.2.5.1 and 8.2.5.
8.2.4 For products produced in large quantities, if the interference is of a continuous nature, the method for determining whether a batch is qualified can be one of the following two statistical methods:
8.2.4.1 Based on the measurement sampling test based on the non-central t distribution, the determination formula for a batch of qualified products is: X+KS...L .
（5）
Xi, the arithmetic mean of the interference level of n samples at a certain measurement frequency point in a sampling, dB; where:
X: is the interference level value of the ith sample at a certain test frequency point, dB, S,=V
(X:-X)(n-1), the standard deviation of the interference level value of n samples at a certain measurement frequency point E in a sampling, dB;
L is the specified allowable value of the interference level, dB; GB3907-83
K is the coefficient derived from the non-central distribution according to the 80%/80% criterion. The K value has a good relationship with the sample size n, and its corresponding values are shown in Table 3.
8.2.4.2 In the counting sampling test based on binomial distribution, the judgment condition for the qualified batch of products is: 11
In a sampling test with a sample size of n, the number of samples with interference level values exceeding the specified interference allowable value should not be greater than the c value corresponding to the sample size n of the batch, otherwise it is judged as unqualified. The relationship between n and c that meets the 80%/80% criterion is shown in Table 4. Table 4
Sample rat
Allowed number of unqualified products c
8.2.4.3 If the result of the sampling test does not meet the requirements of 8.2.4.1 or 8.2.4.2, another sampling can be carried out according to the requirements of 8.2.4.1 or 8.2.4.2. The test results are combined with the results of the first sampling test and judged according to the total number of two samples. 8.2.5 For products produced in large quantities, if the interference is of the intermittent nature, the evaluation method of the measurement results is as follows: 8.2.5.1 If the interference of the product is one of the following three types of intermittent interference*, the measurement results of its interference level shall still be determined in accordance with Clauses 8.2.3 and 8.2.4. The allowable value of interference shall still adopt the allowable value specified for continuous interference. a. Interference of more than two times within 2s, with a duration of no more than 200ms and an interval of no less than 200ms; b. Interference composed of several separate pulses with a single pulse duration of less than 200ms, an interval of less than 200ms, and a continuous cumulative time of more than 200ms; c. Two interferences with an interval of less than 200ms and a continuous cumulative time of more than 200ms. 8.2.5.2 When the interference is of the click nature, a batch of products will have interference The quartile method is used to determine whether the sample is qualified or not. At each measuring frequency point, if the number of countable clicks that exceed the allowable interference value is not greater than one-fourth of the measured number of times, the sample is judged to be qualified. The batch of products can be accepted. The allowable value of click interference is calculated as follows: L+44
+2010og30
Formula: Lk—allowable value of click interference, dB; - allowable value of continuous interference in the corresponding frequency band, dB; L
N click rate.
9Industry Radio interference measurement report
*See the waveform in Appendix B2.
(When N≤0.2)
(When 0.2≤N30)
(When N>30)
Items to be filled in by the product manufacturer or holder Product name, model,
Product number, applicable technical documents,
Manufacturer or user:
Date of manufacture;
Main technical indicators;
Interference Description of suppression measures.
Items to be filled in by the measurement unit
Measurement basis or standard;
Measurement instrument, including antenna type,
Measurement date, environmental conditions,
Operation status of the test product during measurement,
Measurement layout (with attached picture)
Measurement record.
Radio interference level of the test product;
Which standard does it meet or not meet;
Signatures of the measurement staff and participants. GB 3907--83
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