HP 8559A Operation And Service Manual page 47

MODEL 8559A
4-13. RESIDUAL FM (Cont'd)
Comb Generator:
COMB FREQUENCY
INTERPOLATION AMPLITUDE
OUTPUT AMPLITUDE
2. Connect OUTPUT of comb generator to spectrum analyzer INPUT 50Q as shown in Figure 4-5.
The 8559A is sensitive to vibration. Be sure spectrum analyzer is in a
vibration-free environment.
3. Adjust spectrum analyzer TUNING control to display 3.0 GHz signal produced by comb generator.
Adjust REFERENCE LEVEL and REF LEVEL FINE controls to position peak of signal at top graticule
line.
4. Keep 3.0 GHz signal centered on CRT with TUNING control while reducing FREQ SPAN/DIV to zero.
5. Set RESOLUTION BW to 10 kHz and SWEEP TIME/DIV to 0.1 sec.
6. Slightly readjust spectrum analyzer FINE TUNING control until trace appears between fourth and
seventh graticule lines. Peak-to-peak variation of trace should not exceed 1.4 vertical division for each
horizontal division (see Figure 4-7).
For 2201240 line voltages, peak-to-peak variation of trace should not exceed
1.4 vertical divisions (2 kHz) in a 180-series display mainframe.
FREQUENCY VARIATION
OF I F SIGNAL
FIGURE RESIDUAL FM TO AM CONVERSION DISPLAY
PERFORMANCE TESTS
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-
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1 MHz
-
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NOTE
NOTE
AMPLITUDE
VARIATION OF
I F SIGNAL
PERFORMANCE TESTS
Full clockwise
FIGURE 4-7. RESIDUAL FM DISPLAY
100 MC
OFF
div