HP 8340B Manual page 279

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
ss
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
power
than 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] [ENTRY OFF]
on the
DUT. Using the DUT'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 DUT, press [MANUAL], Adjust
the
DUT'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 DUT's POWER
dBm display. The
minimum power displayed should be
>
1 dB above the maximum leveled power
specifications for the
DUT
in Band
4
(19.8 to 26.5 GHz).
If
this is not the case. disconnect the
detector
from the
DUT
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
DUT
and repeat
steps
23 through
30.
SYTM Auto
Tracking (8340B and 8341 B)
31.
Press
[SHIFT] [PEAK]
on the
DUT. The DUT's ENTRY DISPLAY
will
display
"AUTO TRACKING
CALIBRATION". Wait for this display
to
turn
off and then
press
[INSTR PRESET].
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