HP 8340B Manual page 215

5-16. LEVELED RF OUTPUT ADJUSTMENTS
32. Using the OUT's front panel rotary knob (RPG), vary the ALC level from —20 dBm to +20 dBin.
Look for squegging as shown in Figure 5-58. As the power level is increased, you will need to
decrease the vertical sensitivity (CHAN A) and adjust the vertical positions on the oscilloscope. If
any squegging occurs, examine the ENTRY DISPLAY to determine the requested ALC level. If the
ALC level is at or below the maximum specified leveled power, adjust A24R5 (X2C) counter-
clockwise to eliminate the squegging. If the ALC level is above maximum leveled power, what you
are seeing is probably the RF output going unleveled and cannot be adjusted out.
Squegging on the oscilloscope display may appear as shown in Figure
5-58 (power spikes and oscillations) or it may appear as power spikes
without the oscillations. In either case the appropriate adjustment
should be made to eliminate the squegging.
33. On the OUT, press [STARTFREQ] [1] [3]
SWP] [0] [dBm]. Set the oscilloscope's vertical sensitivity to 0.005 V/Div. Vary the ALC
[2]
[-]
level as in step 32 and check for squegging. If any squegging occurs, examine the ENTRY DIS-
PLAY to determine the requested ALC level. If the ALC level is at or below the maximum specified
leveled power, adjust A24R8 (X3C) counter-clockwise to eliminate the squegging. If the ALC level
is above maximum leveled power, what you are seeing is probably the RF output going unleveled
and cannot be adjusted out.
If the OUT is an HP 8341 B, proceed to step 35.
34. On the OUT, press [STARTFREQ] [2] [0] [GHz] [STOPFREQI [2] [6]
SWP] [2] [0] [dBm]. Set the oscilloscope's vertical sensitivity to 0.005 V/Div. Vary the ALC
[-]
level as in step 32 and check for squegging. If any squegging occurs, examine the ENTRY DIS-
PLAY to determine the requested ALC level. If the ALC level is at or below the maximum specified
leveled power, adjust A24R11 (X4C) counter-clockwise to eliminate the squegging. If the ALC level
is above maximum leveled power, what you are seeing is probably the RF output going unleveled
and cannot be adjusted out.
5-110 Adjustments
NOTE
Figure 5-58. Oscilloscope Display with Squegging Present
[5] [GHz][STOPFREQI [2] [0] [GHz][SHIFT][PWR
[.]
(Cont'd)
[5] [GHz][SHIFT][PWR
[.]
HP 8340B/41B