HP 8340B Manual page 212

5-16. LEVELED RF OUTPUT ADJUSTMENTS
LINEAR MODULATOR ALC LOOP GAIN ADJUSTMENTS
Description
The following adjustments are performed to set the ALC loop gain for each band. The adjustment is
done in the power sweep mode, while sweeping the ALC loop from —20 to maximum power.
If the A26 Linear Modulator assembly has not been replaced, adjust-
ments may not be necessary.
23. Connect CHAN A of the oscilloscope to A26TP3 (MOD LVL). Connect CHAN B to A25TP2 (DET).
Set up the oscilloscope as follows:
DISPLAY
CHAN A
CHAN B
TRIGGER
TIME/Div
SWEEP VERNIER
24. On the OUT, press [INSTRPRESET] [SWEEP TIME] [5] [0] [msec]. Press [SHIFTI[PWRSWP]
[-1[2] [0] [dBm]. Press [PWRSWP] [4] [0] [dBm].Press [SHIFT] [CF][2] [0] [0] [MHz] and then
[AM] to turn AM on. Press [CW] [1] [0] [MHz].
The oscilloscope display should be similar to Figure 5-56, Waveforms A and B. It may be neces-
sary to adjust the SWEEP VERNIER to view the entire sweep.
HP 8340B/41B
(Cont'd)
NOTE
CHOP
O.05V Div DC COUPLED
O.05V/Div DC COUPLED
EXT. POS.
5 inS
ON
Adjustments 5-107