Filter
Top Products
5. Log Amplifier Adjustments
Bandpass
Filter Amplitude Adjustment
9. Connect one end of a jumper wire to
A4A3TP8.
Connect the
other end of the jumper to
A4A3TP7
(+
15V).
Connecting the
jumper to
A4A3TP8
first reduces the chance of shorting the +
15V
to ground. Note DVM indication.
V dc
10. Remove the short from between A4A3TP7 and
A4A3TP8.
11. Adjust
A4A3R67
AMPTD for DVM indication the same as that
noted in step 9
f0.0005
V dc. See Figure 3-34 for location of
adjustment. If unable to adjust
A4A3R67
AMPTD for proper
indication, increase or decrease value of
A4A3R66.
(If
A4A3R67
is fully counter-clockwise, increase the value of
A4A3R66.)
Refer to
Table
3-3 for range of values.
12. Repeat steps 9 through 11 until DVM indication is the same
f0.0005
V dc with
A4A3TP7
jumpered
to
A4A3TP8,
and with
A4A3TP7 and
A4A3TP8
not jumpered. Remove the jumper.
-12 VTV and
ATTEN
Adjustments
13. Press LIN pushbutton.
14. Adjust frequency synthesizer output level for DVM indication of
+ 1.000
&IO.0002
V dc.
Synthesizer level:
15.
Press LOG [ENTER
dB/DIV)
dBm
16. Wait three minutes for the log assemblies to stabilize.
17. Decrease the frequency synthesizer output level by 50
dB.
18. Adjust
A4A2R91
-
12 VTV for DVM indication of + 500
f
1
mV
dc.
See Figure 3-34 for location of adjustment.
19. Increase the frequency synthesizer output level by 50
dB
(to the
level of step 14).
20. Adjust
A4A2R61
ATTEN
for DVM indication of + 1.000
*O.OOOl
V
dc. See Figure 3-34 for location of adjustment. If unable to adjust
A4A2R61
ATTEN
for proper indication, increase or decrease value
of
A4A2R62.
(If
A4A2R61
is fully clockwise, increase the value of
A4A2R62.) Refer to
‘Ihble
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
A4A2R61
and
A4A2R91
are interactive, several iterations are
needed.
Linear Gain Adjustments
22. Press LIN pushbutton. DVM indication at
A4AlTPl
should be
+ 1.000
f0.020
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
[*I
CENTER
dB/div]
q.
This disables the
IF step gains.
Adjustments 3-67