HP 8901B Operation And Calibration Manual page 402

Model 8901B Adjustments
c. To eliminate high-frequency roll-off, increase the values of both A19R72 and R74 equally.
d. The effect
of
changing these components is interactive, therefore, whenever a component is
7. Set the spectrum analyzer
to
view
a
+10 dBm signal with a 0
to
2
GHz span width and log
display. Connect its
RF
input to A19J3
(LO
OUT),
or for Option 003, the rear-panel LO OUTPUT
connector.
8. On the Modulation Analyzer, press the blue key then press INSTR PRESET. Key in 55.0 SPCL
to cause the LO to sweep slowly over its doubler range.
9. Adjust A19R41 (DBLR
BAL)
for the minimum level of the
1/2
and
312
harmonics of the doubled
signal over the swept range. The
112
and
312
harmonics should be more than 30
dB
below the
doubled signal. The doubled signal sweeps from approximately 600
to
1300 MHz with a level of
approximately +2 dBm.
(Use values within the range 121
to
6190.)
changed, the power must be rechecked over the entire doubler band.
NOTE
To ewe adjustment, note the frequency of the fundamental where harmonics
are worst, manwzlly tune to that frequency (use the frequency increment
keys to assist in fine tuning), make the adjustment, then key in 55.0 SPCL
and recheck the entire range.
The
sweep can be halted at any time by
pressing the SPCL key.
Adjustment
5
5-11