Adjustment Procedures
5-42 2715 Spectrum Analyzer Service Manual
h. Connect the oscilloscope test probeto TP 8 on theS weepboard.
i. Press Util523Utilto stop the sw eep at center screen.
NOTE. Refer to Figure 5--16. This is a representation of what the waveform at TP8
would look like if the analyzer was sweeping. The scope will be indicating a DC
level. The point indicated in F igure5 --16 w ill need to be adjusted to 0.7 VDC by
adjusting C781.
j. Adjust C781 through its range to locate the midpoint of the waveform
between its extremes. When it has been determ ined that C781 is adjusted
to this point, set C781 for 0.7 VDC. Change the oscilloscope to 0.1
V/Div to increase the accuracy of the adjustmen t.
Setthis point for
0.7VDC with C781
Figure 5-16: Typical FM Adjustment Waveform
k. Remove the probe from TP8 and press AUTO SWEEP twice to restart
the sweep.
l. Connect a FM video signal to the RF IN.
m. Tune the Spectrum Analyzer to an FM visual carrier.
n. Set FM (Satellite) video signal parametersby pressing DEMOD 9 and
selecting SATELLITEVIDEO DETECT MODE, NEGATIVE SYNC
POLARITY,and POSITIVE VIDEO POLARITY. Press any menu
button to exit the menu.