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A
djustment
24.
Last
Converter
Bandpass
Filter
The
purpose
of
this
adjustment
procedure
is
to
verify
or
adjust
the
321.4
MHz
bandpass
lter
response
of
the
A11
last
converter .
1.
Set
the
mainframe
line
switch
to
OFF
.
2.
Remove
the
HP
70908A
RF
section
from
the
mainframe
.
3.
Install
the
extender
module
in
the
mainframe
and
connect
the
HP
70908A
RF
section
to
the
extender
cable
.
4.
Connect
the
equipment
as
shown
in
Figure
7-50.
5.
Set
the
mainframe
line
switch
to
ON
and
allow
at
least
30
minutes
initial
warmup
before
starting
the
adjustment.
6.
Load
and
run
A
djustment
24.
Last
Converter
Bandpass
Filter
.
Refer
to
Chapter
2
for
information
about
running
the
software
.
A
pulse-modulated
carrier
passes
through
the
directional
bridge
to
the
A11
last-converter
321.4
MHz
HIGH
IF
INPUT
.
The
bridge
and
the
A11
last
converter
output
provide
the
inputs
to
channels
B
and
A
of
the
network
analyzer
.
The
resulting
analyzer
display
is
the
A11
bandpass
lter
response
.
A
prompt
instructs
the
user
to
adjust
C15,
C16,
C17,
C18,
and
C19
for
maximum
bandpass
lter
response
at
278.6
MHz.
(This
initial
adjustment
maximizes
the
following
notch
lter
adjustment.)
The
user
next
adjusts
C19
at
278.6
MHz
for
minimum
power
.
C15,
C16,
C17,
and
C18
are
adjusted
for
best
overall
bandpass
lter
response
at
321.4
MHz.
The
test
veries
the
resulting
bandpass
.
Adjustment
Procedures
7-59
Summary of Contents for 70908A
Page 7: ...Servicing at a Glance vi ...
Page 19: ......
Page 44: ...Figure 2 1 Main Menu Softkeys Module Veri cation Software 2 19 ...
Page 45: ...Figure 2 2 Mass Storage Menu and Parameter Menu Softkeys 2 20 Module Veri cation Software ...
Page 47: ...Figure 2 4 Test Menu Softkeys 2 22 Module Veri cation Software ...
Page 55: ......
Page 61: ......
Page 94: ...Troubleshooting the A3 SYTFMD Figure 4 5 Discriminator Output Waveform Troubleshooting 4 33 ...
Page 125: ......
Page 139: ......
Page 205: ......
Page 209: ...Test 01 Flatness Figure 8 2 Equipment Setup for Test 01 Flatness 8 4 Module Veri cation Tests ...
Page 267: ......
Page 271: ...Front Panel Figure 9 2 Front Panel Removal Replacement 1 of 2 9 4 Replacing Major Assemblies ...
Page 272: ...Front Panel Figure 9 3 Front Panel Removal Replacement 2 of 2 Replacing Major Assemblies 9 5 ...
Page 274: ...Rear Panel Figure 9 4 Rear Panel Removal Replacement 1 or 2 Replacing Major Assemblies 9 7 ...
Page 275: ...Rear Panel Figure 9 5 Rear Panel Removal Replacement 2 or 2 9 8 Replacing Major Assemblies ...
Page 284: ...A3 SYTFMD Figure 9 10 A3 SYTFMD Removal Replacement Replacing Major Assemblies 9 17 ...
Page 294: ...A7 2nd Mixer Figure 9 17 A7 2nd Mixer Removal Replacement Replacing Major Assemblies 9 27 ...
Page 329: ......