HP 8568B, Performance Tests And Adjustments Manual, Page: 181 / 313

5. Log Amplifier Adjustments
Filter Amplitude Adjustment
9. Connect one end of a jumper wire to Connect the
other end of the jumper to (+ Connecting the
jumper to first reduces the chance of shorting the +
to ground. Note DVM indication.
V dc
10. Remove the short from between and
11. Adjust AMPTD for DVM indication the same as that
noted in step 9 V dc. See Figure 3-34 for location of
adjustment. If unable to adjust AMPTD for proper
indication, increase or decrease value of (If
is fully counter-clockwise, increase the value of
Refer to 3-3 for range of values.
12. Repeat steps 9 through 11 until DVM indication is the same
V dc with to and with
and not jumpered. Remove the jumper.
-12 VTV and Adjustments
13. Press LIN pushbutton.
14. Adjust frequency synthesizer output level for DVM indication of
+ 1.000 V dc.
Synthesizer level:
Press LOG
[
ENTER
16. Wait three minutes for
the
log assemblies to stabilize.
17. Decrease
the
frequency synthesizer output level by 50
18. Adjust 12 VTV for DVM indication of + 500 1 dc.
See Figure 3-34 for location of adjustment.
19. Increase the frequency synthesizer output level by 50 (to the
level of step 14).
20. Adjust for DVM indication of + 1.000 V
dc. See Figure 3-34 for location of adjustment. If unable to adjust
for proper indication, increase or decrease value
of (If is fully clockwise, increase
the
value of
Refer to 3-3 for range of values.
21. Repeat steps 17 through 20, until specifications of steps 18 and
20
are achieved without further adjustment. Because adjustments
and are interactive, several iterations are
needed.
Linear Gain Adjustments
22. Press LIN pushbutton. DVM indication at should be
+ 1.000 V dc (+ 0.980 to + 1.020 V dc). If indication is
not within this range, repeat steps 14 through 21. If indication is
within this range, press
C
ENTER
This disables the
IF step gains.
Adjustments 3-67