1、GM DAEWOO Auto interference voltage (incorrect expression for this meaning) : Voltage created between two points on two separated conductors by electromagnetic wave disturbance and measured to the specified conditions. 3.11. Narrow band emission : Emission having a narrower bandwidth than that of a
2、specific measuring device or receiver 3.12. Peak value demodulator : A demodulator in which the output voltage becomes the peak value of the applied signal 3.13. Quasi-peak value demodulator : A demodulator having a specified electric time constant, it transmits the output voltage corresponding to t
3、he split value of the peak pulse value when the regularly repeated same pulse is applied. The split ratio increase to come closer to 1 as the pulse repetition rate increases. 3.14. Electromagnetic wave environment : All electromagnetic phenomena present in a given location. 3.15. Shielded enclosure
4、; shielded room: Nets or thin metal housing specially designed to separate the interior and exterior environments electromagnetically 4. REQUIREMENTS FOR VEHICLE ELECTROMAGNETIC EMISSION MEASURING 4.1. General test conditions and test plan 4.1.1. Test plan note A test plan shall be established for e
5、ach test item. In the test plan, the test frequency band, emission limit line, disturbance source classification (wide band source (long cycle, short cycle) or narrow band source), antenna type or position, test report requirements, supply voltage and other factors shall be specified. 4.1.2. Judgmen
6、t of Suitability with Limit Line If the type of the interference is not found, it is necessary to decide whether the measured electromagnetic wave emission is the narrowband or broadband to apply the right limit line as indicated by the test plan. The figure 1 suggests a standard for the decision of
7、 such suitability. EDS-T-5521RADIO INTERFERENCE TEST PAGE: 3/10 ISSUED DATE: 1994. 11. 11 REVISED DATE: 2008. 11. 04 VERSION: 4 GM DAEWOO Auto & Technology 4.1.3. Disturbance source category - Electromagnetic disturbance sources can be classified into the following three types: a. Continuous/long cy
8、cle wide band and automatically activated short cycle device b. Manually activated short cycle wide band disturbance source c. Narrow band disturbance source 4.1.4. Types of wide band disturbance sources Table 1. Types of wide band disturbance sources (Category according to cycle) Continuous cycle L
9、ong cycle Short cycle Ignition system Wiper motor Power antenna Active driving control device Heater blower motor Washer pump motor Furl injection device Rear wiper motor Door mirror motor Instrument regulator A/C compressor Central door lock Alternator Engine cooling Power seat 4.1.5. Types of narr
10、ow band disturbance sources Microprocessor, digital logic, oscillator, clock generator, etc. 4.1.6. Operating conditions During test, all continuous cycle and long cycle systems shall operate in the respective maximum RF noise generating conditions. All systems that can be operated Intermittently an
11、d continuously (or systems controlled to realize temperature equilibrium) may be operated continuously. EDS-T-5521RADIO INTERFERENCE TEST PAGE: 4/10 ISSUED DATE: 1994. 11. 11 REVISED DATE: 2008. 11. 04 VERSION: 4 GM DAEWOO Auto & Technology Figure 1. Method of judging the suitability of emitted/cond
12、ucted electromagnetic wave emitter 5. MEASURING EQUIPMENT 5.1. Requirements of measuring equipment EDS-T-5521RADIO INTERFERENCE TEST PAGE: 5/10 ISSUED DATE: 1994. 11. 11 REVISED DATE: 2008. 11. 04 VERSION: 4 GM DAEWOO Auto & Technology Measuring equipment shall meet requirements in 16-1 of Internati
13、onal Radio Interference Committee. 5.2. Receiver 5.2.1. Type The measuring receiver shall meet requirements in 16-1 of International Radio Interference Committee. Manual or automatic frequency scanning may be used. The overload, linearity, selectivity and normal response level to the pulse shall be
14、specially considered. Note)The spectrum analyzer and scanning receiver are especially useful for measurement of radio disturbance devices. The peak demodulation type provides much better indication than the quasi-peak demodulation type in the same bandwidth. Radiation noise can be measured convenien
15、tly when the peak demodulator, which provides much faster scan speed than the quasi-peak demodulator, is used. When evaluating the whole frequency, the peak demodulator is used for efficiency. However, for better reproducibility of the measured results and correct comparison, use of the quasi-peak d
16、emodulator is recommended. 5.2.2. Minimum scan time The scan rate of the receiver shall meet requirements for the frequency band and demodulation type determined by International Radio Interference Committee. The frequency versus minimum scan time (or, the fastest scan rate) is shown in Table 1. Tab
17、le 2. Minimum scan time Band Peak demodulator Quasi-peak demodulator 9K 150KHz Do not apply Do not apply 150K 30MHz 100 l / 200 s/ 30M 1000 1 l / or 100 l / * 20 s/ Note - *When 9 bandwidth is used, 100l / shall be used. 5.2.3. Measuring equipment bandwidth The bandwidth of the measuring equipment s
18、hall be set to the level at least 6f below the noise lowest limit curve. The bandwidth is shown in Table.2. Note) When the bandwidth of the measuring equipment exceeds that of the narrow band signal, the measured signal size is not affected. The indicated value of the impulse wide band noise becomes
19、 lower as the measuring equipment bandwidth reduces. Table 3. Bandwidth of measuring equipment (6f ) Frequency band Wide band peak Wide band Quasi-peak Narrow band peak Narrow band average 150K 30 9KHz 9KHz 9KHz 9KHz FM broadcast 120 120 120 120 30M1000 Mobile service 120 120 120 9 EDS-T-5521RADIO I
20、NTERFERENCE TEST PAGE: 6/10 ISSUED DATE: 1994. 11. 11 REVISED DATE: 2008. 11. 04 VERSION: 4 GM DAEWOO Auto & Technology If the spectrum analyzer is used for peak measuring, video bandwidth of the equipment shall be at least 3 times the resolution bandwidth. 5.3. Antenna & Impedance matching unit Ant
21、enna Type Use the antenna equipped in a vehicle as the antenna for measurement. The location & type of the vehicle antenna shall be decided by the specification of the vehicle. If it is not an antenna with a vehicle (like mobile radio system), the test can be proceeded by using the antenna in the ta
22、ble 4. And the form and location of the antenna shall be stated in the test plan. Table 4. Antenna type Band Antenna type L W - A M 1m mono-pole MW - AM 1m mono-pole SW - AM 1m mono-pole broadcast VHF - FM 1m mono-pole 30 - 54 mono-pole 70 - 87 mono-pole 144 - 172 mono-pole 420 - 512 mono-pole Mobil
23、e service 800 - 1000 mono-pole LW : LONG WAVE, MW : MEDIUM WAVE SW : SHORT WAVE, VHF : VERY HIGH FREQUENCY 5.3.1. Requirement for Measuring Equipment (1) Broadcast band In case of the measurement in each broadcast band, used equipment shall be satisfied by the following conditions. 1) AM broadcast b
24、and Long wave: 150KHz - 300KHz Medium wave: 530KHz - 2MHz Short wave: 5.9M - 6.2MHz The measuring system shall satisfy the following conditions. The output impedance of the impedance matching unit: 50 resistance Gain: The gain of the measuring equipment (or attenuation) shall be within the accuracy
25、of 0.5dB. Also, the equipment gain for each frequency band shall be within the envelope of 6dB like the figure 2. EDS-T-5521RADIO INTERFERENCE TEST PAGE: 7/10 ISSUED DATE: 1994. 11. 11 REVISED DATE: 2008. 11. 04 VERSION: 4 GM DAEWOO Auto & Technology The calibration is executed like the procedure ex
26、plained in Clause 9. Compression Point: The 1dB compression point is generated when the voltage level of sine wave is over 60fo . Measuring Equipment Noise Floor: The noise floor of the entire equipment including the measuring equipment, amplifier, & free amp shall be lower than the limit level by 6
27、f . Dynamic Range: The section between 1dB compression points in the noise floor Input Impedance: The impedance of the measuring equipment for the input of matching unit shall be more than the opening circuit impedance of the artificial antenna network described in Clause 9 by at least 10 times. Fig
28、ure 2. Example of Gain Curve 2) FM broadcast band (87M - 108MHz) Measure it with the measuring equipment with 50 of the input impedance. If SWR is over 2:1, the input matching unit used. It needs to adjust the attenuation/gain of the matching unit a proper way. 3) Mobile service band (30M - 1000MHz)
29、 Measure it with the measuring equipment of 50 & antenna of 50 . When the impedance of the measuring equipment & antenna is different, use a proper error corrector. 6. TEST METHOD 6.1. Measure the interference voltage playing in the terminal of the radio-receiving antenna properly located in a vehic
30、le. 6.2. Operate each interference under the normal working condition to judge each electromagnetic wave interference or the characteristic of the electromagnetic wave interference of the electromagnetic interference system. (to decide transient effect) 6.3. The interference voltage, reference, is m
31、easured at the end of the receiver of the antenna coaxial cable connected to the grounded connector. Ground the antenna connector with the housing part of the on-board radio. The radio housing is grounded with the vehicle body by using the real vehicle harness. The surface current can be EDS-T-5521R
32、ADIO INTERFERENCE TEST PAGE: 8/10 ISSUED DATE: 1994. 11. 11 REVISED DATE: 2008. 11. 04 VERSION: 4 GM DAEWOO Auto & Technology curbed by using the quality double shield cable at the connecting end of the measuring receiver and method of string the ferrite ring. The coaxial bulkhead connector is used
33、to connect to the measuring receiver outside the shield room. (Refer to figure3) 6.4. In some cases where the radio receiver can be located in various sites like an instrument panel or under the seat, execute the test on the location of each radio receiver. Figure 3. Test Configuration Diagram (When
34、 using monopole antenna) 7. TEST RESULT EVALUATION STANDARD The limit line for each interference is not the same. The heater blower motor, long-cycle interference, is lower than the short-cycle interference in terms of limit line. Since the short-cycle interference like the door mirror motor usually
35、 is operated for 12 seconds, the limit line has more room to set up. However, the unique energy generating from devices like the microprocessor is similar to the original signal and can affect the neighboring systems so that the limit line shall be severely set. (Table 5) EDS-T-5521RADIO INTERFERENC
36、E TEST PAGE: 9/10 ISSUED DATE: 1994. 11. 11 REVISED DATE: 2008. 11. 04 VERSION: 4 GM DAEWOO Auto & Technology Table 5. Limit Line for Interference Noise Voltage in Receiver Antenna Terminal (fo ) Band Frequency Band Continuous Cycle Band Short-Cycle Narrow Band(* *) MHz Quasi-Peak Peak Quasi-Peak Pe
37、ak Peak LW 0.15 - 0.30 9 22 15 28 6 MW 0.53 - 2.0 6 19 15 28 0 SW 5.9 - 6.2 6 19 6 19 0 VHF 30 - 54 6 (15*) 28 15 28 0 VHF 70 - 87 6 (15*) 28 15 28 0 VHF 87 - 108 6 (15*) 28 15 28 6 VHF 144 - 172 6 (15*) 28 15 28 0 UHF 420 - 512 6 (15*) 28 15 28 0 UHF 800 - 1000 6 (15*) 28 15 28 0 Annotation) 1. Bro
38、adband values specified in this table are effective for the bandwidth specified in table 2. 2. In the FM broadcast band, the stereo signal is more sensitive than the mono signal so that it is good to apply this to the value of VHF (87 M-108M) band. * Value is the limit value for the ignition system.
39、 (* *) LW : LONG WAVE MW : MEDIIM WAVE SW : SHORT WAVE VHF : VERY HIGH FREQUENCY UHF : ULTRA HIGH FREQUENCY 8. ANTENNA MATCHING UNIT 8.1. Antenna Matching Unit Factor (150KHz - 6.2MHz) Requirements for the measuring instrument in Clause 3.2.1 are stated. 8.2. Antenna Matching Unit -Calibration The a
40、rtificial antenna network in Figure 4 means the antenna including the coaxial cable. 60 capacity indicates the capacity of the coaxial cable between the vehicle antenna & vehicle radio input. 8.2.1. Gain Measurement The antenna matching unit is used to decide whether the gain meets the requirements
41、of Clause 5.3.2.1.1 by using the setup of Figure 4. 8.2.2. Test Procedure (1) Set the starting carrier frequency as the 40 f (o ) output level in the state of 1KHz, 30% amplitude EDS-T-5521RADIO INTERFERENCE TEST PAGE: 10/10 ISSUED DATE: 1994. 11. 11 REVISED DATE: 2008. 11. 04 VERSION: 4 GM DAEWOO A
42、uto & Technology modulation (2) Draw the gain curve y each frequency segment. 8.3. Impedance Measurement Use the vector impedance measuring instrument (or equal test equipment) to measure the output impedance of the antenna & antenna matching unit. The output impedance whose center is (50+j0) (e.g. SWR 2:1) on the Smith Cart is in the circle passing (100+j0) . Fig 1 CALIBRATION SET-UP 9. REFERENCE 9.1. CISPR 25 : Limits And Methods of Measurement of Radio Disturbance Characteristics for the Protection of Receivers Used on Board Vehicles 9.2. SAE J551/4 ISSUED JUN 94
