Performance Verification: AnalogS ection
WFM90D and WFM91D ServiceManual 4-13
8. Increasethe frequency on the leveled sine wave generator until the edge of
the circledisplay expands out to the compass rose and again reduces to the
--3 dB (70%) point gaps on the vertical graticule axis. See Figure 4--1.
9. Check that the frequencyreadout on the leveled sine wave generator is
between 3.98 and 4.18 MHz (4.83 and5. 03 MHzPAL).
10. Adjust the frequencyon the leveled sine wavegenerator until the edge of the
circledisplay reaches the --3dB (70%) point gaps on the horizontal graticule
axis.
11. Check that the frequency readout on the leveled sine wave generatoris
between 3.98 and 4.18 MHz (4.83 and5. 03 MHzPAL).
12. Remove all signals from the WFM90D or WFM91D monitor.
Audio Gain and Frequency Response
This procedureverifies the following requirement:
MeasurementAccuracy: 0.5 dB at 1 kHz. Frequency Response: 0.5 dB from
50 Hz to 20 kHz.
1. Connect the output fromthe audio generator to the AUDIO IN connector on
the WFM90D or WFM91D monitor.
2. Set the audio generatorfor a 1 kHz tone output, with an amplitude of
+8.0 dBu. Select Signal On.
3. Select AUDIO display mode on the WFM90D or WFM91D monitor.
4. Enter the Operatingmenu and select 8dBu.
5. Check that the display amplitude is within 0.5 dB of the reference level
graticulelines.
6. Set the audio generatorfor a +4.0 dBu output amplitude.
7. Select 4dBufrom the Operating menu.
8. Check that the display amplitude is within 0.5 dB of the reference level
graticulelines.
9. Set the audio generatorfor a 0.0 dBu output amplitude.
10. Select 0dBufrom the Operating menu.
11. Check that the display amplitude is within 0.5 dB of the reference level
graticulelines.
12. Set the audio generatorfor a --10.0 dBu output amplitude.