Some standard content:
National Metrology Technical Specification of the People's Republic of China JJF1144—2006
Calibration Specification for EMI Testing Receivers Issued on 2006-05-23
Implementation on 2006-0823
Issued by the General Administration of Quality Supervision, Inspection and Quarantine JJF 1144—2006
Calibration Specification for EMI Testing Receivers
JJF 1144—2006
This specification was approved by the General Administration of Quality Supervision, Inspection and Quarantine on May 23, 2006, and came into effect on August 23, 2006.
Responsible unit: National Technical Committee on Radio Metrology Main drafting unit: China National Institute of Metrology Participating drafting unit: Shenzhen Institute of Metrology and Quality Inspection, Telecommunication Research Institute, Ministry of Information Industry
Rohde & Schwarz
This specification is interpreted by the National Technical Committee on Radio Metrology Main drafters of this specification:
Xu Dinghua
Teng Junheng
Participating drafters:
Lu Bingsong
Yang Yanzhang
J JF1144—2006
(China National Institute of Metrology)
(China National Institute of Metrology)
(China National Institute of Metrology)
(Institute of Telecommunications, Ministry of Information Industry)
(Shenzhen Institute of Metrology and Quality Inspection)
(Rohde & Schwarz)
Scope·
References-
3Terms
4Overview
5Metrological characteristics·
5.1 Frequency reading ·
5.2 Level indication,
5.3 Passband of the whole machine
5.4 Pulse response ·
IF rejection ratio
5.6 Image rejection ratioWww.bzxZ.net
Attenuator
Linearity indication ·
5.9 Voltage standing wave ratio at RF input port
6 Calibration conditions
6.1 Environmental conditions
6.2 Main equipment used for calibration ·
7 Calibration items and calibration Methods ·
7.1 Check appearance and normality of operation
Calibration of frequency·.
7.3 Calibration of immunity to interference from opponents
7.46FB Calibration of bandwidth·
Calibration of noise indication
Calibration of voltage indication·
Calibration of indication linearity
Calibration of attenuator…
Calibration of pulse response characteristics·
7.10 Voltage standing wave ratio at RF input terminal
JJF 1144—2006
7.11 Explanation of electromagnetic disturbance measurement receiver with spectrum analyzer function Calibration results
9 Recalibration interval·
Appendix A Calibration data record table
1 Scope
JJF1144—2006
Calibration specification for electromagnetic disturbance measurement receiver
This specification is applicable to the calibration of electromagnetic disturbance measurement receivers that are newly manufactured, newly purchased, in use, and after repair and adjustment, with a frequency range of 9kHz to 1000MHz and meet the requirements of GB/16113. Other electromagnetic disturbance measurement receivers covering this frequency band can be implemented as a reference. 2 References
JJG501—2000 "Spectrum Analyzer"
GB/T6113.1-1995 "Specification for Radio Disturbance and Immunity Measuring Equipment" GB/T6113.2-1998 "Radio Disturbance and Immunity Measuring Methods" JF1059—1999 "Evaluation and Expression of Measurement Uncertainty" CISPR 16-4-2: 2003 Specification for radio disturbance and immunity measuring ap-paratus and methods Part 4-2 Uncertainties, Statistics and Limiting Measurement Instrumentation Uncertainty
When using this specification, attention should be paid to the use of the current valid versions of the above references. 3 Terminology
3.1 Electromagnetic disturbance Any electromagnetic phenomenon that may cause the performance of a device, equipment or system to degrade or cause damage to living or non-living matter.
3.2 Bandwidth bandwidth (B,)
The width of the total selectivity curve of the electromagnetic disturbance measurement receiver at a specified level below the midpoint of the response curve, represented by the symbol B. n represents the specified level in decibels. 3.3 Impulse strength (IS) Impulse strength (sometimes also called pulse area) is defined as the time-integrated area of a certain pulse voltage: IS
Where: IS - pulse strength, μV·so3.4 Image rejection ratio imagerejectionratioV(t)dt
The ratio of the specified signal level at the image frequency of the electromagnetic disturbance measurement receiver to the (useful) signal level at the tuned frequency that produces the same output power.
JJF1144—2006
3.5 Intermediate frequency rejection ratio The ratio of the specified signal level at any intermediate frequency used in the electromagnetic impedance measurement receiver to the useful signal level producing the same output power:
4 Overview
The electromagnetic interference measurement receiver is mainly used for the measurement of electromagnetic interference signals such as continuous wave signals and pulse signals. It has a large measurement dynamic range and high sensitivity. The principle block diagram is shown in Figure 1. The functions of each part of the attenuator are as follows: Figure 1 Block diagram of electromagnetic disturbance measurement receiver Audio output 1) Input attenuator can attenuate the excessive signal or interference level from the outside, adjust the attenuation level, ensure that the level input to the electromagnetic disturbance measurement receiver is within the indication range of the electromagnetic disturbance measurement receiver, and avoid the damage of the electromagnetic disturbance measurement receiver caused by overvoltage or current. 2) The RF amplifier uses the principle of frequency selection amplification to select only the required measurement signal to enter the lower circuit, while all kinds of external spurious signals (including image frequency signals, intermediate frequency signals, intermodulation harmonic signals, etc.) are excluded. 3) The mixer synthesizes the RF signal from the RF amplifier and the signal from the local oscillator to generate a difference frequency signal and input it to the intermediate frequency amplifier. Since the frequency of the difference frequency signal is lower than the frequency of the RF signal, the gain of the intermediate frequency amplifier is improved.
4) The local oscillator provides a high-frequency oscillation signal with a stable frequency. 5) Intermediate frequency amplifier Since the tuning circuit of the intermediate frequency amplifier can provide a strict bandwidth and obtain a high gain, the overall selectivity and sensitivity of the receiver are guaranteed. 6) Detector The detection method of the electromagnetic disturbance measurement receiver is different from that of the ordinary receiver. In addition to receiving sinusoidal wave signals, the electromagnetic disturbance measurement receiver is more commonly used to measure the pulse disturbance level. Therefore, in addition to the average value detection function and bee value detection function that are usually equipped, the electromagnetic disturbance measurement receiver also adds a quasi-peak detection function.
7) Output indication Some electromagnetic disturbance measurement receivers use a meter to indicate the electromagnetic disturbance level, and some use a digital display. General electromagnetic disturbance measurement receivers have speakers that emit disturbance sounds. 5 Metering characteristics
5.1 Frequency reading
S.1.1 Range: 9kHz～1000MHz
JJF 1144--2006
5.1.2 Accuracy: not more than ±(frequency×reference frequency accuracy+half of the last displayed unit)5.2 Level indication
5.2.1 Level measurement range: (0～120)dB(μV)5.2.2 Maximum allowable error: ±2dB
5.3 Passband of the whole machine
5,3.16dB bandwidth
A band frequency range: 9kHz～150kHz, bandwidth requirement: 0.2kHz:1 band frequency range: 0.15MHz30MHz, bandwidth requirement: 9kHz; C band frequency range: 30MHz～300MHz, bandwidth requirement: 120kHzD band frequency range: 300MHz～1000MHz, bandwidth requirement: 120kHz5.3.2 Maximum allowable bandwidth error; ±10%5.4 Pulse response
5.4.1 The pulse response value of the pulse specified in Table 2 shall comply with the limit values specified in Table 1Table 1 Pulse response of electromagnetic disturbance measurement receiverSingle and complex frequency
Isolated pulse
(9150) kHz
See Note ①
-3.0 ±1.0
0 (reference)
+7.5±1.5
+13.0±2.0
+17.0±2.0
+ 19.0±2.0
When the calibration frequency band is constant, the relative equivalent level of the pulse B (0. 15 ~30) MHz
-4.5±1.0
0(reference）
+6.5±1.0
+10.0±1.5
+20.5±2.0
+22.5±2.0
+ 23.5±2.0
(30 300) MI Iz
-8.0±1.0
0reference
+9.0±1.0
+ 14.0 ± 1. 5
+26.0 ±2.0
+28.5±2.0
+31.5±2.0
(300 ~ 1000) MHz
-8.0±1.0
0Base
+ 14.0±1.5
+26.0 ±2.0
+28.5±2.0*
+31.5±2.0*
Note: ① In the frequency range of 9～150kHz, when the repetition frequency is higher than 100Hz, the response of this frequency band cannot be clearly defined due to the pulse overlap phenomenon of the intermediate frequency amplifier. ②) When the frequency is higher than 300MLz, the pulse response is limited due to the input load of the electromagnetic interference detection receiver. The values marked with * in Table 1 are optional and not mandatory. At the transition frequency point, the off-band technical requirements shall be followed. For example, the 0.15MHz frequency point shall follow the technical requirements of the (U,15~30)MIIz frequency band.
5.5 Intermediate frequency suppression ratio = 40dB
5.6 Image frequency suppression ratio = ≥40dB
5.7 Attenuator
5.7.1 Range: (0~110) dB
5.7.2 Maximum allowable error: ±1dB
5.8 Linear indication
5.8.1 Range: (0~30)d3
5.8.2 Maximum allowable error: ±1dB
JJF 1144—2006
5.9 VSWR at RF input: ≤2, when RF attenuation is 0dB ≤1.2, when RF attenuation is not less than 10dB Note: No qualified or unqualified conclusion is made for calibration. Usually the maximum allowable error required above is for reference only. Calibration conditions
6.1 Environmental conditions
6.1.1 Temperature: (10~30)℃, temperature fluctuation during calibration is less than ±2℃6.1.2 Relative humidity: (30~75)%
6.1.3 AC power supply: 220V±11V, 50Hz±1Hz6.1.4 There is no electromagnetic interference and mechanical vibration around that may affect normal calibration work. 6.2 Main equipment for calibration
Frequency counter
Frequency measurement range: 9kHz～1000MHz
Frequency measurement accuracy: ±1×10-7
Resolution: 0.1Hz
6.2.2 Power meter
Frequency range: 9kHz～1000MHz
Power measurement range and maximum allowable error: (-70～+30)dBm, =0.1dB6.2.3 Signal generator
Frequency range and frequency accuracy: 9kHz--1050MHz, ±1×10-7Output range Range and maximum allowable error: (0~126)dEB (μV), ±0.1dB/10dB, cumulative ±2dB Harmonic distortion: <-30dBc
Phase noise: <-110dBc/Hz (deviation from carrier frequency 1kHz) <-120dBc/Hz (deviation from carrier frequency 10kHz) 6.2.4 Standard variable attenuator
Frequency range: 1XC~1000MHz
Attenuation range: (0~110)dB,
Uncertainty: ±0.02d13/10dB
6.2.5 Pulse calibration source
JJF 1144—2006
0.1dB step
Pulse frequency range: 0.1Hz～1000MHzThe test pulse characteristics of the pulse calibration source shall meet the requirements of Table 2Table 2 Pulse characteristics of pulse calibration source
Frequency range
(9-150) kHz
(0.15 --30) MHz
(30 300) MFIz
(300 - 1000) MHz
6.2.6 Network analyzer
Pulse intensity
Frequency range: 9kHz～1000MHz
6.2.7 Connectors, converters, cables, etc.
Minimum average spectrum
Upper limit/MHz
Repetition frequency
100，60，25，10，5，2,1，Banwen pulse 1000，100，20，10,2,1，Isolated pulse 1000，100，20，10,2,1，Isolated pulse 1000，100，20，10
6.2.8 All calibration instruments shall be calibrated and qualified, shall be within the validity period of verification or calibration, and shall be traceable. 6.2.9 All calibration instruments shall be preheated as required and their operation shall be carried out in accordance with their respective manuals. 7 Calibration Items and Calibration Methods
7.1 Appearance and Normal Operation Inspection
7.1.1 The electromagnetic disturbance measurement receiver to be calibrated shall be equipped with necessary accessories and manuals. 7.1.2 All buttons, switches, knobs and connectors of the electromagnetic disturbance measurement receiver to be calibrated shall be firmly installed, with clear on and off, clear conversion, flexible knobs, correct positioning, and no mechanical damage that affects the normal operation. 7.1.3 The electromagnetic disturbance measurement receiver to be calibrated shall be able to operate normally after power-on and have a clear display. 7,14 After the instrument is preheated as required, it shall be fully calibrated. 7.2 Frequency Calibration
7.2.1 Reference Frequency Calibration
7.2.1.1. The reference output of the electromagnetic disturbance measurement receiver to be calibrated shall be connected to the input of the frequency counter, as shown in Figure 2. 7.2.1.2 The frequency counter shall be set to the highest resolution. 7.2.1.3 The calibrated electromagnetic disturbance measurement receiver shall be tested with the frequency counter 15 minutes after it is turned on. Record the data in Table A, 1 in Appendix A. α
Electromagnetic disturbance
Measurement receiver
JJF 1144—2006
Reference output
Frequency counter
Figure 2 Calibration of reference frequency
7.2.2 Calibration of intermediate frequency output frequency
7.2.2.1 The intermediate output of the calibrated electromagnetic disturbance measurement receiver is connected to the input of the frequency counter, as shown in Figure 3. The intermediate output of the electromagnetic weak disturbance
Measurement receiver
is connected to the input of the frequency counter, as shown in Figure 3. 7.2.2.2 The frequency counter is set to the highest resolution 7.2.2.3 The calibrated electromagnetic disturbance measurement receiver shall be tested with the frequency counter 15 minutes after it is turned on. Record the data in Table A.2 of Appendix A.
7.2.3 Calibration of frequency reading accuracy
7.2.3.1 Connect the output of the signal generator to the input of the electromagnetic disturbance measurement receiver. 7.2.3.2 Set the detector of the electromagnetic disturbance measurement receiver to the peak detection mode and the attenuator to the automatic mode. 7.2.3.3 Set the signal generator frequency to 100kHz and the level to 90dB(V). Set the frequency of the electromagnetic disturbance measurement receiver to 100kHz and the bandwidth to 9kHz. Fine-tune the frequency of the signal generator to maximize the level indication value of the electromagnetic disturbance measurement receiver and record the frequency of the signal generator as the actual value of the frequency. 7.2.3.4 Calculate the error according to formula (2):
8, f×100%
8,--relative error of frequency indication,%;fo——actual value of frequency, MHz;
f——nominal value of frequency, MHz.
7.2.3.5Measure at 9kHz, 20kHz, 50kHz, 150kHz, 2MHz, 4MHz, 8MHz, 12MHz, 16MHz, 20MHz.26MHz, 30MHz, 40MHz, 50MHz, 90MHz, 100MHz, 200MHz, 300MHz, 500MHz, 800MHz, 1000MHz. In the frequency range of 9kHz to 150kHz, the bandwidth is selected as 200Hz, in the frequency range of 150kHz to 30MHz, the bandwidth is selected as 9kHz, and the bandwidth of other frequency points is selected as 120kHz. Repeat 7.2.3.1~7.2.3.4 and record the data in Table A.3 of Appendix A. 7.3 Calibration of immunity to interference
7.3.1 Calibration of the first intermediate frequency image frequency response 7.3.1.1 The signal generator input is connected to the power meter through a power divider on one side and to the electromagnetic disturbance measurement receiver to be calibrated on the other side, as shown in Figure 4.
Signal generator
JJF 1144--2006
Power divider
Figure 4 Calibration of the first intermediate frequency image frequency response Power meter
Electromagnetic interference
Measurement receiver
7.3.1.2 Set the signal generator frequency to fs, and adjust the level so that the power meter displays -10dBmo7.3.1.3 Set the electromagnetic disturbance measurement receiver to low noise mode, the detector to average detection mode, and the intermediate frequency bandwidth to an appropriate bandwidth. Set the electromagnetic disturbance measurement receiver frequency to fs, read the electromagnetic disturbance measurement receiver level value, and record it as Ls.
7.3.1.4 Adjust the signal generator frequency to f=fs+2f (when the local oscillator frequency is higher than the signal frequency) or f=fs-2F1 (when the local oscillator frequency is lower than the signal frequency), and the level is the same as that in 7.3.1.2. Where /IFi is the first intermediate frequency of the electromagnetic disturbance measurement receiver. 7.3.1.5 Read the level L (dBm) at the frequency f of the electromagnetic disturbance measurement receiver to be calibrated. Calculate according to formula (3). Record the data and calculation results in Table A.4 of Appendix A. a Ls-
7.3.1.6 Repeat 7.3.1.1 to 7.3.1.5 according to the frequency specified in Table A.4 of Appendix A. 7.3.2 Calibration of the second intermediate frequency image frequency response 7.3.2.1 Set the signal generator frequency to fs and adjust the level so that the power meter displays -10dBmc (3)
7.3.2.2 Set the electromagnetic disturbance measurement receiver to low noise mode, the detector to average detection mode, and the intermediate frequency bandwidth to 1kHz. Set the frequency fs of the electromagnetic disturbance measurement receiver and read the level value indicated by the electromagnetic disturbance measurement receiver, recorded as Ls.
7.3.2.3 Adjust the signal generator frequency to J=fs+2.fin2 (when the local oscillator frequency is higher than the signal frequency) or f;=fs-2.frF2 (when the local oscillator frequency is lower than the signal frequency), the level is the same as the level in 7.4.1.2. Where f1F2 is the second intermediate frequency of the electromagnetic disturbance measurement receiver.
7.3.2.4 Read the voltage L at the frequency of the electromagnetic disturbance measurement receiver to be calibrated, (dBm). Calculate according to formula (4). Record the data and calculation results in Table A.5 of Appendix A: ae = Ls - L1
7.3.2.5 Repeat 7.3.1.1 to 7.3.1.4 according to the frequency specified in Table A.5 of Appendix A. 7.3.3 Calibration of intermediate frequency rejection ratio
7.3.3.1 The signal generator is connected to the power meter through a power divider on one side and to the electromagnetic disturbance measurement receiver to be calibrated on the other side, as shown in Figure 4.
JJF 1144—2006
7.3.3.2 Set the electromagnetic disturbance measurement receiver to low noise mode, the detector to average detection mode, and the frequency to be calibrated.
7.3.3.3 Set the signal generator frequency to fs=f, and adjust the voltage so that the power meter displays -10dI3m. Among them, f is the first intermediate frequency frequency of the frequency band corresponding to the set frequency of the electromagnetic disturbance measurement receiver. 7.3.3.4 Read the level L (dBm) on the electromagnetic disturbance measurement receiver to be calibrated. Calculate according to formula (5). Record the data and calculation results in Table A.6 of Appendix A. α. =- 10 - Lr
7.3.3.5 Follow the frequency requirements specified in Table A.6 of Appendix A. Repeat 7.3.3.1 to 7.3.3.4. Calibration of 7.46dB bandwidth
7.4.1 Connect the output of the signal generator to the input of the electromagnetic disturbance measurement receiver. (5)
7.4.2 Set the attenuator of the electromagnetic disturbance measurement receiver to automatic, the detector to average, and set it to low noise mode.
7.4.3 Set the signal generator output to 70dB (uV) and the frequency to 10VHzc7.4.4 Set the test frequency of the electromagnetic interference measurement receiver to 10MHz and the bandwidth to 9kH, fine-tune the frequency of the electromagnetic interference measurement receiver, and find the maximum value of the level indication. Adjust the output level of the signal source so that the level display of the electromagnetic interference measurement receiver is 70dB (uV). 7.4.5 Increase the frequency of the signal source so that the level display value of the electromagnetic interference measurement receiver is 64dB (uV), read the frequency of the signal generator, and record it as ft;-6da(uv); reduce the frequency of the multiple generator so that the level display value of the electromagnetic interference measurement receiver is 64dB (uV), read the frequency of the signal generator, and record it as /L\6adrav. Calculate the 6dB bandwidth according to formula (6), and calculate the error of the 6dB bandwidth according to formula (7). Afs = f上(-6 dB()] - fF[-6B(m)]Af. -Afs
Where: Af is the nominal value of bandwidth.
7.4.6 Repeat 7.4.1 to 7.4.5 at 100kHz, 100MHz and 500MHz. The bandwidth of the electromagnetic disturbance measurement receiver at 100kHz is set to 200Hz, and the bandwidth of the electromagnetic disturbance measurement receiver at 100MHz and 500MHz is set to 120kHz. The 6dB bandwidth value is recorded in Table A.7 in Appendix A. 7.5 Calibration of noise indication
7.5.1 Connect a 500 terminal load to the RF input of the electromagnetic disturbance measurement receiver. 7.5.2 Set the attenuator of the electromagnetic disturbance measurement receiver to 0dB and the test time to 100ms. 7.5.3 Record the noise indication value of the electromagnetic disturbance measurement receiver according to the frequency points and settings required in Table A.8 in Appendix A.5 Read the level L (dBm) at the frequency f on the calibrated electromagnetic disturbance measurement receiver. Calculate according to formula (3). Record the data and calculation results in Table A.4 of Appendix A. a Ls-
7.3.1.6 Repeat 7.3.1.1 to 7.3.1.5 according to the frequency specified in Table A.4 of Appendix A.7.3.2 Calibration of the second intermediate frequency image frequency response7.3.2.1 Set the signal generator frequency to fs and adjust the level so that the power meter displays -10dBmc(3)
7.3.2.2 Set the electromagnetic disturbance measurement receiver to low noise mode, the detector to average detection mode, and the intermediate frequency bandwidth to 1kHz. Set the frequency fs of the electromagnetic disturbance measurement receiver and read the level value indicated by the electromagnetic disturbance measurement receiver, recorded as Ls.
7.3.2.3 Adjust the signal generator frequency to J=fs+2.fin2 (when the local oscillator frequency is higher than the signal frequency) or f;=fs-2.frF2 (when the local oscillator frequency is lower than the signal frequency), the level is the same as the level in 7.4.1.2. Where f1F2 is the second intermediate frequency of the electromagnetic disturbance measurement receiver.
7.3.2.4 Read the voltage L at the frequency of the electromagnetic disturbance measurement receiver to be calibrated, (dBm). Calculate according to formula (4). Record the data and calculation results in Table A.5 of Appendix A: ae = Ls - L1
7.3.2.5 Repeat 7.3.1.1 to 7.3.1.4 according to the frequency specified in Table A.5 of Appendix A. 7.3.3 Calibration of intermediate frequency rejection ratio
7.3.3.1 The signal generator is connected to the power meter through a power divider on one side and to the electromagnetic disturbance measurement receiver to be calibrated on the other side, as shown in Figure 4.
JJF 1144—2006
7.3.3.2 Set the electromagnetic disturbance measurement receiver to low noise mode, the detector to average detection mode, and the frequency to be calibrated.
7.3.3.3 Set the signal generator frequency to fs=f, and adjust the voltage so that the power meter displays -10dI3m. Among them, f is the first intermediate frequency frequency of the frequency band corresponding to the set frequency of the electromagnetic disturbance measurement receiver. 7.3.3.4 Read the level L (dBm) on the electromagnetic disturbance measurement receiver to be calibrated. Calculate according to formula (5). Record the data and calculation results in Table A.6 of Appendix A. α. =- 10 - Lr
7.3.3.5 Follow the frequency requirements specified in Table A.6 of Appendix A. Repeat 7.3.3.1 to 7.3.3.4. Calibration of 7.46dB bandwidth
7.4.1 Connect the output of the signal generator to the input of the electromagnetic disturbance measurement receiver. (5)
7.4.2 Set the attenuator of the electromagnetic disturbance measurement receiver to automatic, the detector to average, and set it to low noise mode.
7.4.3 Set the signal generator output to 70dB (uV) and the frequency to 10VHzc7.4.4 Set the test frequency of the electromagnetic interference measurement receiver to 10MHz and the bandwidth to 9kH, fine-tune the frequency of the electromagnetic interference measurement receiver, and find the maximum value of the level indication. Adjust the output level of the signal source so that the level display of the electromagnetic interference measurement receiver is 70dB (uV). 7.4.5 Increase the frequency of the signal source so that the level display value of the electromagnetic interference measurement receiver is 64dB (uV), read the frequency of the signal generator, and record it as ft;-6da(uv); reduce the frequency of the multiple generator so that the level display value of the electromagnetic interference measurement receiver is 64dB (uV), read the frequency of the signal generator, and record it as /L\6adrav. Calculate the 6dB bandwidth according to formula (6), and calculate the error of the 6dB bandwidth according to formula (7). Afs = f上(-6 dB()] - fF[-6B(m)]Af. -Afs
Where: Af is the nominal value of bandwidth.
7.4.6 Repeat 7.4.1 to 7.4.5 at 100kHz, 100MHz and 500MHz. The bandwidth of the electromagnetic disturbance measurement receiver at 100kHz is set to 200Hz, and the bandwidth of the electromagnetic disturbance measurement receiver at 100MHz and 500MHz is set to 120kHz. The 6dB bandwidth value is recorded in Table A.7 in Appendix A. 7.5 Calibration of noise indication
7.5.1 Connect a 500 terminal load to the RF input of the electromagnetic disturbance measurement receiver. 7.5.2 Set the attenuator of the electromagnetic disturbance measurement receiver to 0dB and the test time to 100ms. 7.5.3 Record the noise indication value of the electromagnetic disturbance measurement receiver according to the frequency points and settings required in Table A.8 in Appendix A.5 Read the level L (dBm) at the frequency f on the calibrated electromagnetic disturbance measurement receiver. Calculate according to formula (3). Record the data and calculation results in Table A.4 of Appendix A. a Ls-
7.3.1.6 Repeat 7.3.1.1 to 7.3.1.5 according to the frequency specified in Table A.4 of Appendix A.7.3.2 Calibration of the second intermediate frequency image frequency response7.3.2.1 Set the signal generator frequency to fs and adjust the level so that the power meter displays -10dBmc(3)
7.3.2.2 Set the electromagnetic disturbance measurement receiver to low noise mode, the detector to average detection mode, and the intermediate frequency bandwidth to 1kHz. Set the frequency fs of the electromagnetic disturbance measurement receiver and read the level value indicated by the electromagnetic disturbance measurement receiver, recorded as Ls.
7.3.2.3 Adjust the signal generator frequency to J=fs+2.fin2 (when the local oscillator frequency is higher than the signal frequency) or f;=fs-2.frF2 (when the local oscillator frequency is lower than the signal frequency), the level is the same as the level in 7.4.1.2. Where f1F2 is the second intermediate frequency of the electromagnetic disturbance measurement receiver.
7.3.2.4 Read the voltage L at the frequency of the electromagnetic disturbance measurement receiver to be calibrated, (dBm). Calculate according to formula (4). Record the data and calculation results in Table A.5 of Appendix A: ae = Ls - L1
7.3.2.5 Repeat 7.3.1.1 to 7.3.1.4 according to the frequency specified in Table A.5 of Appendix A. 7.3.3 Calibration of intermediate frequency rejection ratio
7.3.3.1 The signal generator is connected to the power meter through a power divider on one side and to the electromagnetic disturbance measurement receiver to be calibrated on the other side, as shown in Figure 4.
JJF 1144—2006
7.3.3.2 Set the electromagnetic disturbance measurement receiver to low noise mode, the detector to average detection mode, and the frequency to be calibrated.
7.3.3.3 Set the signal generator frequency to fs=f, and adjust the voltage so that the power meter displays -10dI3m. Among them, f is the first intermediate frequency frequency of the frequency band corresponding to the set frequency of the electromagnetic disturbance measurement receiver. 7.3.3.4 Read the level L (dBm) on the electromagnetic disturbance measurement receiver to be calibrated. Calculate according to formula (5). Record the data and calculation results in Table A.6 of Appendix A. α. =- 10 - Lr
7.3.3.5 Follow the frequency requirements specified in Table A.6 of Appendix A. Repeat 7.3.3.1 to 7.3.3.4. Calibration of 7.46dB bandwidth
7.4.1 Connect the output of the signal generator to the input of the electromagnetic disturbance measurement receiver. (5)
7.4.2 Set the attenuator of the electromagnetic disturbance measurement receiver to automatic, the detector to average, and set it to low noise mode.
7.4.3 Set the signal generator output to 70dB (uV) and the frequency to 10VHzc7.4.4 Set the test frequency of the electromagnetic interference measurement receiver to 10MHz and the bandwidth to 9kH, fine-tune the frequency of the electromagnetic interference measurement receiver, and find the maximum value of the level indication. Adjust the output level of the signal source so that the level display of the electromagnetic interference measurement receiver is 70dB (uV). 7.4.5 Increase the frequency of the signal source so that the level display value of the electromagnetic interference measurement receiver is 64dB (uV), read the frequency of the signal generator, and record it as ft;-6da(uv); reduce the frequency of the multiple generator so that the level display value of the electromagnetic interference measurement receiver is 64dB (uV), read the frequency of the signal generator, and record it as /L\6adrav. Calculate the 6dB bandwidth according to formula (6), and calculate the error of the 6dB bandwidth according to formula (7). Afs = f上(-6 dB()] - fF[-6B(m)]Af. -Afs
Where: Af is the nominal value of bandwidth.
7.4.6 Repeat 7.4.1 to 7.4.5 at 100kHz, 100MHz and 500MHz. The bandwidth of the electromagnetic disturbance measurement receiver at 100kHz is set to 200Hz, and the bandwidth of the electromagnetic disturbance measurement receiver at 100MHz and 500MHz is set to 120kHz. The 6dB bandwidth value is recorded in Table A.7 in Appendix A. 7.5 Calibration of noise indication
7.5.1 Connect a 500 terminal load to the RF input of the electromagnetic disturbance measurement receiver. 7.5.2 Set the attenuator of the electromagnetic disturbance measurement receiver to 0dB and the test time to 100ms. 7.5.3 Record the noise indication value of the electromagnetic disturbance measurement receiver according to the frequency points and settings required in Table A.8 in Appendix A.5. The bandwidth of the electromagnetic disturbance measurement receiver at the 100kHz frequency point is set to 200Hz, and the bandwidth of the electromagnetic disturbance measurement receiver at the 100MHz and 500MHz frequency points is set to 120kHz. The 6dB bandwidth value is recorded in Table A.7 in Appendix A. 7.5 Calibration of noise indication
7.5.1 Connect a 500 terminal load to the RF input of the electromagnetic disturbance measurement receiver. 7.5.2 Set the attenuator of the electromagnetic disturbance measurement receiver to 0dB and the test time to 100ms. 7.5.3 Record the noise indication value of the electromagnetic disturbance measurement receiver according to the frequency points and settings required in Table A.8 in Appendix A.5. The bandwidth of the electromagnetic disturbance measurement receiver at the 100kHz frequency point is set to 200Hz, and the bandwidth of the electromagnetic disturbance measurement receiver at the 100MHz and 500MHz frequency points is set to 120kHz. The 6dB bandwidth value is recorded in Table A.7 in Appendix A. 7.5 Calibration of noise indication
7.5.1 Connect a 500 terminal load to the RF input of the electromagnetic disturbance measurement receiver. 7.5.2 Set the attenuator of the electromagnetic disturbance measurement receiver to 0dB and the test time to 100ms. 7.5.3 Record the noise indication value of the electromagnetic disturbance measurement receiver according to the frequency points and settings required in Table A.8 in Appendix A.
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