5-16.
LEVELED RF OUTPUT ADJUSTMENTS
(Cont’d)
14. On the OUT, press [CW] [1] [7]
[.]
[5] [GHz]. Adjust A24R8 (X3C) for a MOD LEVEL trace as
described
in step 13.
If the OUT is an HP 8341 B, proceed with step 16.
15. On the OUT, press [CW] [2] [3]
[.]
[3] [0Hz] and adjust A24R11 (X4C) for a MOD LEVEL trace
as
described in step 13.
16. Set the oscilloscope to DISPLAY A and set CHAN A to 0.02 V/Div.
17.
Press
[RECALL] [2] on the OUT. The oscilloscope display should be similar to Figure 5-54.
Adjust
A24R12 (MIN) so that all points on the trace are reduced to the lowest possible voltage level (i.e.,
maximum negative voltage).
18. On the OUT, press [RECALL][1][CW][7] [GHz].Set the oscilloscope for DISPLAY CHOP, CHAN
A to 0.5
V/Oiv, and CHAN B to 0.5 V/Div.
19. Using the OUT’s
[~]
and
[~]
step keys, step through Band 2 from 7 to 13.4 GHz and check for
an
optimum SRO bias trace (Figure 5-55, Waveform A, B, and C) at each step. If not optimum,
adjust A24R1 (OFF A) if the frequency is closer to 7 GHz, or adjust A24R2 (OFF B) if the OUT
frequency is closer to 13.5 GHz. If an adjustment is made, step through the entire band again,
making sure every step is optimized
or acceptable if all the steps cannot be optimized.
20. Using the OUT’s [a.] and
[~‘]
step keys, step through Band 2 from 7
to 13.4 GHz and readjust
A24R5 (X2C) if necessary to
improve the MOO LEVEL trace. Also, adjust A24R1 (OFF A) and
A24R2 (OFF B) if necessary to optimize
the SRD Bias as in step
19
above. If any adjustments are
made, step through Band 2 again until the SRD bias and the MOD LEVEL trace is optimized. It will
not be possible to adjust
the MOD LEVEL trace for optimum
at each step,
so adjust for best
compromise trace across Band 2 (see Figure 5-55, Waveforms 0 and E).
NOTE
The SRD bias trace is adjusted in Band 2 with A24R1 (OFF A) and A24R2
(OFF B) set for optimum. It should not require any other adjustments in
Bands 3 or 4, unless the SRD bias trace is bad as shown in Figure 5-55. If
either the OFF A or OFF B controls are adjusted in Bands 3 or 4, then
each band will have to be rechecked, starting with Band 2 at 7 GHz and
stepping through each band.
21. On the OUT, press [CW] [1] [3]
[.]
[5] [0Hz]. Using the OUT’s
[~]
and
[~]
step keys, step
through Band 3 from 13.5 to
19.9 GHz and readjust A24R8 (X3C) if necessary to
achieve the best
MOO LEVEL trace across Band 3.
If the OUT is an HP 8341B, proceed to the LINEAR MODULATOR ALC LOOP GAIN
ADJUSTMENTS.
22. On the OUT, press [CW] [2] [0]
[.]
[1] [0Hz]. Using the OUT’s step keys, step through Band 4
from
20.1
to
26.5 GHz and readjust A24R11 (X4C) if necessary for the best MOD LEVEL trace
across Band 4.
5-106
Adjustments
HP 8340B/41B
