5-14.
UNLEVELED RF OUTPUT ADJUSTMENTS (Cont’d)
Adjust A24R10 (X4B) to optimize the power in the second half of the display.
If the
output
power begins to decrease while adjusting one of these potentiometers (pots) clock-
wise (i.e., power reversal, squegging), adjust the pot counter-clockwise until the power is peaked
again and then continue turning the pot counter-clockwise until the power is reduced
0.5 dB.
It may be desirable
to optimize the power in one half of the band (maximum power with no
squegging), even though squegging is induced in the other half. One would do this if the side being
adjusted is significantly lower in powerthan the other half. Once the power is optimized, adjust the
bias in the other half (using the pot for that half) to eliminate squegging. Iterate between the two
adjustments to optimize the power and to ensure that there is no squegging in either half.
27. If BP2 FREQ
and BP2 have been adjusted, readjust them for maximum power across the band. If
BP3 FREQ and BP3 have been adjusted, readjust them for maximum power in the second half of
the display.
28. Access Cal Constant
74 by
pressing [SHIFT][GHz] [7] [4] [Hz] [SHIFT][ENTRYOFF]
on the
OUT. Using the OUT’s rotary knob, adjust Cal Constant 74 to peak the power across the entire
band (adjust above and below 1024).
29. Repeat step 26.
30. Note the position of the minimum power point on the scope. On the OUT, press [MANUAL].Adjust
the OUT’s rotary knob until the dot on
the scope is near the position noted as the minimum power
point. Slowly vary the position of the dot around this point while observing the OUT’s
POWER
dBin display. The minimum power displayed should be
>
1 dB above the maximum leveled power
specifications for the OUT in Band 4 (19.8 to 26.5
GHz). If this is not the case, disconnect the
detector from the OUT and connect
the power meter and power sensor to the attenuator. Again,
slowly vary the rotary knob and determine the power level of the minimum power point. If it is still
<1 dB above the maximum leveled power specification, press [CONT]on the
OUT and repeat
steps 23 through 30.
SYTM Auto Tracking
(8340B and 8341 B)
31. Press [SHIFT]
[PEAK]
on the
OUT.
The
OUT’s ENTRY DISPLAY will display “AUTO TRACKING
CALIBRATION”. Wait for this display to turn off and then press [INSTRPRESET].
SYTM DELAY COMPENSATION ADJUSTMENTS BY BAND
Band 4 Delay Compensation (HP 8340B), Band 3 Delay Compensation (HP 8341 B)
32. Connect the scope and detector as shown in Figure 5-40. The scope should be set for A vs B
mode.
5-80
Adjustments
HP 8340B/41B