Khz If - HP 8901B Operation And Calibration Manual

Adjustments Model 8901B
7. On the Modulation Analyzer, key in 3000 kHz
to
tune the Modulation Analyzer
to
the
signal
image. Again switch between PEAK+ and PEAK-. The difference between the two readings
should be less
than
1.6 kHz. If it is not, adjust A18R23 again
to
diminish the difference by one
h a l f .
Now note the reading for PEAK+ (PKl+) and PEAK- (PK1-).
Press fi
kHz.
Note the
reading for PEAK+ (PK2+) and PEAK- (PK2-). The instrument is adjusted properly when:
I(PKl+ - PK1-)
+
(PK2+
-
PK2-)(
<
1.6 kHz.
(Ideally, PK1+ should equal PK2-, and PK1- should
equal
PK2+.)
8. Connect the FM+4 output of the AM/FM test source
to
the Modulation Analyzer's INPUT.
9. On the Modulation Analyzer, set LP FILTER
to
3 kHz. Press AUTOMATIC OPERATION.
10. Set the audio analyzer's oscillator frequency
to
1 kHz and level for a display of 50 kHz deviation
11.
On
the Modulation Analyzer, press AM. Adjust A18R19 (INC
AM
1.5 MHZ
IF) for a minimum
on the Modulation Analyzer.
display (but less than 0.2%).
NOTE
The
specification for incidental AM requires that 0.5 times the residual
AM be subtracted out. The residual FM can be measured by momentarily
disconnecting the audio input
to
the AM/FM test source and noting the
displayed AM. Subtracting 0.5 times the displayed AM from the AM
measurement in step 11 gives the actual incidental AM.
5-20 Adjustment 12