音頻測(cè)試方法_Measure_method_of_Philips_FM_radio

1、Equipment: RF-generator SML & Audio-analyzer UPL Philips Semiconductors, Bart Bouma, 4-April-2006 56 TEA5761/64 Bench Test set-up at Philips Applied Filters: IEC tuner (cut-off at 15 kHz A-weighting filter (ear curve Audio Analyzer + weighting filters R&S UPL Freq XX MHz, Level variable R&S SML02 L

2、R PC BUSINTER FACE DATA CLOCK TEA5761 2 1 Input level 4 3 Philips Semiconductors, Martijn Ophoff, 11-7-2005 48 Philips Semiconductors BL Personal Entertainment Solutions Index 1 2 3 4 5 6 7 8 9 10 11 Hardware setup 1 . 2 Hardware setup 2 . 3 Sensitivity . 4 THD . 5 RDS sensitivity . 6 Image Rejectio

3、n (High Side. 8 Image Rejection (Low Side. 9 Audio Output Voltage . 10 Audio L/R Imbalance. 11 Audio Band Limits / Audio Frequency Response . 12 Audio Stereo Separation . 13 _ 1 of 13 Philips Semiconductors BL Personal Entertainment Solutions 1 Hardware setup 1 Equipment: I2C board Main board Applic

4、ation board Software Audio analyzer Signal generator Power Supply PR37156 PR73002 i.e. GH328 with the TEA5764 on it TEA576x R&S UPL R&S SML01 Agilent E3630A Connection scheme: Audio analyser Figure 1: General measurement set-up _ 2 of 13 Philips Semiconductors BL Personal Entertainment Solutions 2 H

5、ardware setup 2 Equipment: I2C board Main board Application board Software Audio analyzer Signal generator Power Supply Combiner PR37156 PR73002 i.e.GH328 with the TEA5764 on it TEA576x R&S UPL R&S SML01 Agilent E3630A Mini circuits Connection scheme: Signal generator #1 combiner Signal generator #2

6、 Audio analyser Figure 2: Advanced measuring set-up _ 3 of 13 3 SensitivitySensitivity is the ability of a tuner to pick up FM radio stations. The higher the sensitivity, the better the tuners ability to bring in weaker stations clearly. A good sensitivity figure will indicate the tuners ability to

7、pull in a moderately distant station mostly noise-free and in stereo. The lower the number how better is the tuners ability of the FM radio. The number for mono will be lower than for stereo.1. Connect test equipment as shown in Figure 1.2. Configure the tuner with the TEA576X software:Set frequency

8、 = 98.0 MHz.Set de-emphasis = 50 s3. Configure the audio analyzer:Select Analyzer button ANLR “8”.Set function = THD+N / SINAD.Set Measurement Mode = SINAD.Set Dyn Mode = PrecisionSet Meas Time = SlowSet unit ch1 = dBSet Filter = A WeightingSet Frequency Limit Low = 300 HzSet Frequency Limit High =

9、15000 Hz4. Configure the generator:Set carrier frequency = 98.0 MHz.Select FM Modulation.Set FM Deviation = 22.5 KHz.Set source = LFGEN.Set LFGEN frequency = 1 KHz.Enable modulationEnable carrier5. Adjust generator RF level, VRF , until audio analyzer SINAD = 26 dB +/- 1 dB.6. Mono Sensitivity (VEMF

10、 = VRF =Vpd x 2 = .VEMF R DUT =504 THDThe total harmonic distortion, or THD , of a signal is a measurement of the harmonic distortion present, that is, any departure of the output signal waveform from that which should result from the input signal waveforms being operated on by the systems specified

11、 or ideal transfer function. In most cases, this ideal transfer function is linear and time-invariant. When a signal passes through a non-linear device, additional content is added at the harmonics of the original frequencies. Thisis a measurement of the extent of that distortion. The measurement is

12、 most commonly the ratio of the sum of the powers of all harmonicfrequencies above the fundamental frequency to the power of the fundamental: In this calculation, V n means the RMS voltage of harmonic n. The THD is usually expressed in percent as distortion factor or in dB as distortion attenuation.

13、 THD+N means total harmonic distortion plus noise. This measurement is much more common and more comparable between devices. This is usually measured by inputting a sine wave, notch filtering it, and measuring the ratio between the signal with and without the sine wave.1. Connect test equipment as s

14、hown in Figure 1.2. Configure the tuner with the TEA576X software:Set frequency = 98.0 MHzSet de-emphasis = 50 s3. Configure the audio analyzer:Select Analyzer button ANLR “8”Set function = THD+N/SINADSet MEAUREMENT Mode = THD+NSet Dyn Mode = PrecisionSet Meas Time = SlowSelect Unit = %Set Filter =

15、A WeightingSet FrqLim low = 300 HzSet FrqLim high = 15000Hz4. Configure generator:Set carrier frequency = 98.0 MHzSelect FM ModulationSet FM Deviation = 75 KHzSet RF level = 54 dBVpd (0.5mVpd =1mVEMF Set source = LFGENSet LFGEN frequency = 1 KHzEnable modulationEnable carrier5. Record THD (% = .%5 R

16、DS sensitivity1. Connect test equipment as shown in Figure 1.2. Configure generator:Set carrier frequency = 98.0 MHz.Select FM stereo Modulation.Set FM Deviation = 67.5 kHz.Set source = LFGEN.Set Mode = RSet LFGEN frequency = 1 KHz.Set Pre-emphasis = 50s.Set Pilot Deviation 6.75 kHzSet ARI State = O

17、FFSet RDS State = ONSet RDS deviation 2.00 kHz2. Configure the tuner with the TEA576X software:Set FM ON/RDS ONSet frequency = 98.0 MHzSet de-emphasis = 50 sSet DAVMSK-bit ONSwitch on in the “system” window the read mode to “on INTX” (see 2 Open RDS control windowClick on Data Monitor (see 3Choose i

18、n the RDS control for the “Two block update” option (see3 statistics field will change. Adjust generator VRF level until the average-quality field shows a value of 95% (5.To start a new measurement (refresh the BQR field click on the monitor reset button (6. To do a correct measurement you will need

19、 more then 2000 groups (7, which have an average BQR of 95% NOTE 1: Check if the “Data overflow” is red than you are missing some data. If so than try to close all other applications on your PC if it is still red than your PC is not fast enough to get the dataNOTE 2: Each time you change the RF inpu

20、t level click on the monitor reset button to start a new measurement.6 Image Rejection (High Side1. Connect test equipment as shown in Figure 1.2. Configure the tuner with the TEA576X software:Set frequency = 98.0 MHz.Set RFAGC = ON.Set Hi Side Injection = ONDe-emphasis = 50 sec3. Configure the audi

21、o analyzer:Select Analyzer button ANLR “8”.Set function = RMS Select.Set units = dBV.Set Bandwidth = BP 3%.Set Freq Mode: fix: 1000 Hz.Set Filter: A Weighting4. Configure generator:Set carrier frequency = 98.0 MHz.Set RF level = 25 dBVpd value.Select FM Modulation.Set FM Deviation = 22.5 KHz.Set sou

22、rce = LFGEN.Set LFGEN frequency = 1 KHz.Enable modulation.Enable carrier.5. Record the audio level, VAUDIO0=.dBV.6. Adjust generator VRF1level until the audio level, V AUDIO1 = VAUDIO0 3 dB =.dBV V RF1 =.dB V7. Configure generator:Set carrier frequency = 98.450 MHzSet unit = dBV.Select FM Modulation

23、Set FM Deviation = 22.5 KHz.Set source = LFGEN.Set LFGEN frequency = 1 KHz.Enable generatorEnable carrier.8. Adjust generator VRF2 level until the audio level, V AUDIO2 = VAUDIO1.V RF2 =.dB V9. Image rejection IRdB V = VRF2 VRF1 =. dBV dBV =. dBV7 Image Rejection (Low Side1. Connect test equipment a

24、s shown in Figure 1.2. Configure the tuner with the TEA576X software:Set frequency = 98.0 MHz.Set RFAGC = ON.Set Hi Side Injection = OFFDe-emphasis = 50 sec3. Configure the audio analyzer:Select Analyzer button ANLR “8”.Set function = RMS Select.Set units = dBV.Set Bandwidth = BP 3%.Set Freq Mode: f

25、ix: 1000 Hz.Set Filter: A Weighting4. Configure generator:Set carrier frequency = 98.0 MHz.Set RF level = 25 dBVpd value.Select FM Modulation.Set FM Deviation = 22.5 KHz.Set source = LFGEN.Set LFGEN frequency = 1 KHz.Enable modulation.Enable carrier.5. Record the audio level, VAUDIO0=.dBV.6. Adjust

26、generator VRF1level until the audio level, V AUDIO1 = VAUDIO0 3 dB =.dBV V RF1 =.dB V7. Configure generator:Set carrier frequency = 97.550 MHzSet unit = dBV.Select FM ModulationSet FM Deviation = 22.5 KHz.Set source = LFGEN.Set LFGEN frequency = 1 KHz.Enable generatorEnable carrier.8. Adjust generat

27、or VRF2 level until the audio level, V AUDIO2 = VAUDIO1.V RF2 =.dB V9. Image rejection IRdB V = VRF2 VRF1 =. dBV dBV =. dBV8 Audio Output Voltage1. Connect test equipment as shown in Figure 1.2. Configure the tuner with the TEA576X software:Set frequency = 98.0 MHz.De-emphasis = 50 sec3. Configure t

28、he audio analyzer:Select Analyzer button ANLR “8”.Set function = RMS Select.Set units = V.Set Bandwidth = BP 3%.Set frequency mode = Freq Mode: fix: 1000 Hz. Set Filter = A-Weighting4. Configure generator:Set carrier frequency = 98.0 MHz.Set RF level = 54 dBVpd (0.5mVpd =1mVEMF Select FM Modulation.

29、Set FM Deviation = 22.5 KHz.Set source = LFGEN.Set LFGEN frequency = 1 KHz.Enable modulation.Enable carrier.5. Audio level (VRMS = VAUDIO0 = V rms .9 Audio L/R Imbalance1. Connect test equipment as shown in Figure 1.2. Configure the tuner with the TEA576X software:Set frequency = 98.0 MHz.De-emphasi

30、s = 50 sec3. Configure the audio analyzer:Select Analyzer button ANLR “8”.Set Channel = 1&2Set function = RMS Select.Set units ch1= dBV.Set units ch2= dBV.Set Bandwidth = BP 3%.Set frequency mode = Freq Mode: fix: 1000 Hz.Set Filter = A-Weighting4. Configure generator:Set carrier frequency = 98.0 MH

31、z.Set RF level = 54 dBVpd (0.5mVpd =1mVEMF Select FM Modulation.Set FM Deviation = 22.5 KHz.Set source = LFGEN.Set LFGEN frequency = 1 KHz.Enable modulation.Enable carrier.5. Left channel audio level (dBV = VAUDIOL =dBV.6. Right channel audio level (dBV = VAUDIOR =dBV.7. Audio L/R Imbalance (dBV=abs

32、(VAUDIOL V AUDIOR = =.dBV-.dBV=.dBV.10 Audio Band Limits / Audio Frequency Response1. Connect test equipment as shown in Figure 1.2. Configure the tuner with the TEA576X software:Set frequency = 98.0 MHz.Set De-emphasis = 50s.3. Configure the audio analyzer:3.1 Select Analyzer button ANLR “8”.3.2 Se

33、t FREQ/PHASE = Frequency3.2 Set function = RMS Select.3.3 Set units = dBV.3.4 Set Bandwidth = BP 3%.3.5 Set frequency mode = Freq Mode: FREQ CH1.3.6 Do not use any filters so put all FILTERS OFF4. Configure generator:4.1 Set carrier frequency = 98.0 MHz.4.2 Set RF level = 54 dBVpd (0.5mVpd =1mVEMF 4.3 Select FM stereo Modulation.4.4 Set FM Deviation = 10 kHz.4.5 Set source = LFGEN.4.6 Set Mode L = 1, R = 0.4.6 Set LFGEN frequency = 1 KHz.4.7 Set Pre-emphasis = 50s.5. Audio 1 kHz level (dBV= V1KHz =dBV.6. Configure generator LFGEN frequency = 20 Hz. (Do step 4.6 again; LFGEN frequency =2