Troubleshooting
the
A13
ALC/Bias
The
A13
ALC/bias
provides
the
drive
signals
for
the
A1
leveling
amplier
and
the
A2
LO
multiplier
.
The
A2
LO
multiplier
gate
bias
is
a
voltage
divider
adjustment.
The
A2
LO
multiplier
block
takes
the
detected
output
information
from
the
A2
LO
multiplier
and
compares
it
with
a
A2
LO
multiplier
voltage
reference
.
This
information
is
integrated
and
sent
back
to
the
A2
LO
multiplier
attenuator
.
Multiplier
band
switching
takes
decoded
band
information
from
A10
power
supply/driver
(BC1,BC2,BC4)
and
enables
the
appropriate
paths
inside
the
A2
LO
multiplier
to
achieve
the
LO
frequency
necessary
for
fundamental
mixing
inside
the
A3
SYTFMD .
Refer
to
A2
LO
multiplier
troubleshooting
for
switching
logic
per
band.
LOLA
Output
Switch/Leveling
The
LOLA
output
switch
takes
band
information
from
the
A10
power
supply/driver
(BC0)
and
sends
the
pin
switch
biasing
to
the
A1
leveling
amplier
for
switching
the
LO
output
to
either
the
A15
RF
1st
converter
(.0000001
to
2.9
GHz)
or
the
A3
SYTFMD
(2.9
to
22
GHz
Input).
The
LOLA
leveling
circuitry
takes
the
detected
output
from
the
A1
leveling
amplier
and
compares
it
to
a
reference
voltage
from
A1.
This
information
is
integrated
and
sent
to
the
A1
leveling.
When
the
LO
input
power
to
the
A1
is
low
,
PIN
diodes
1
and
2
are
at
minimum
attenuation.
As
the
input
power
increases
,
A13Q9
gradually
biases
PIN
diode
2
to
maximum
attenuation,
leaving
PIN
diode
1
to
respond
to
small
changes
in
power
.
LO
gate
bias
is
a
voltage
divider
bias
adjustment
scheme
.
Multiplier
Leveling
Circuit
Tune
the
HP
70000
Series
modular
measurement
system
to
a
center
frequency
of
8
GHz
with
a
span
of
100
MHz.
Connect
a
DVM
to
the
A
TTEN
pin
of
the
A2
LO
multiplier
.
Connect
one
side
of
a
jumper
wire
to
ground.
T
ouch
the
other
side
of
the
jumper
wire
to
the
REF
pin
of
the
A2.
The
voltage
at
the
A
TTEN
pin
should
be
less
than
+1.5
V
.
Remove
the
jumper
from
the
REF
pin
and
connect
it
to
the
DET
pin
of
the
A2.
The
voltage
at
A
TTEN
should
be
greater
than
+11
V
.
If
either
of
the
voltages
is
incorrect,
troubleshoot
the
A13
ALC/bias .
LO
Leveling
Amplier
Leveling
Circuit
Tune
the
HP
70000
Series
modular
measurement
system
to
a
center
frequency
of
8
GHz
with
a
span
of
100
MHz.
Connect
one
side
of
a
jumper
wire
to
ground.
Connect
the
other
side
of
the
jumper
to
the
REF
pin
of
the
A1
leveling
amplier
.
The
voltage
at
A1
PIN
1
should
be
+10.5
V
,
and
PIN
2
+1.3
V
.
Remove
the
jumper
from
the
REF
pin
and
connect
it
to
the
DET
pin
of
the
A1
leveling
amplier
.
The
voltage
at
PIN
1
should
be
3.5
V
and
the
voltage
at
PIN
2
should
be
1.75
V.
If
any
voltages
are
incorrect,
troubleshoot
the
A13
ALC/bias.
4-48
T
roubleshooting
Содержание 70908A
Страница 7: ...Servicing at a Glance vi ...
Страница 19: ......
Страница 44: ...Figure 2 1 Main Menu Softkeys Module Veri cation Software 2 19 ...
Страница 45: ...Figure 2 2 Mass Storage Menu and Parameter Menu Softkeys 2 20 Module Veri cation Software ...
Страница 46: ...Figure 2 3 Equipment Menu and HP MSIB Map Screen Menu Softkeys Module Veri cation Software 2 21 ...
Страница 47: ...Figure 2 4 Test Menu Softkeys 2 22 Module Veri cation Software ...
Страница 55: ......
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Страница 88: ...Troubleshooting the A1 Leveling Ampli er Figure 4 2 Notch Filter Waveform Troubleshooting 4 27 ...
Страница 94: ...Troubleshooting the A3 SYTFMD Figure 4 5 Discriminator Output Waveform Troubleshooting 4 33 ...
Страница 117: ...Overall Block Diagram of RF Section Back page for Foldout Goes Here This is just a place holder 4 56 Troubleshooting ...
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Страница 128: ...External Frequency Reference Figure 6 1 Preferred Frequency Reference Connections System Calibration 6 3 ...
Страница 130: ...External Frequency Reference Figure 6 4 Using an HP 8566B Spectrum Analyzer and a House Standard System Calibration 6 5 ...
Страница 139: ......
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Страница 209: ...Test 01 Flatness Figure 8 2 Equipment Setup for Test 01 Flatness 8 4 Module Veri cation Tests ...
Страница 253: ...Test 23 RF Input Return Loss Figure 8 25 Equipment Setup for Test 23 RF Input Return Loss 8 48 Module Veri cation Tests ...
Страница 257: ...Test 25 LO Input Return Loss Figure 8 27 Equipment Setup for Test 25 LO Input Return Loss 8 52 Module Veri cation Tests ...
Страница 267: ......
Страница 271: ...Front Panel Figure 9 2 Front Panel Removal Replacement 1 of 2 9 4 Replacing Major Assemblies ...
Страница 272: ...Front Panel Figure 9 3 Front Panel Removal Replacement 2 of 2 Replacing Major Assemblies 9 5 ...
Страница 274: ...Rear Panel Figure 9 4 Rear Panel Removal Replacement 1 or 2 Replacing Major Assemblies 9 7 ...
Страница 275: ...Rear Panel Figure 9 5 Rear Panel Removal Replacement 2 or 2 9 8 Replacing Major Assemblies ...
Страница 277: ...Bandpass Filter Figure 9 6 Bandpass Filter Removal Replacement 1 or 2 9 10 Replacing Major Assemblies ...
Страница 278: ...Bandpass Filter Figure 9 7 Bandpass Filter Removal Replacement 2 or 2 Replacing Major Assemblies 9 11 ...
Страница 280: ...A1 Leveling Ampli er Figure 9 8 A1 Leveling Ampli er Removal Replacement Replacing Major Assemblies 9 13 ...
Страница 282: ...A2 LO Multiplier Figure 9 9 A2 LO Multiplier Removal Replacement Replacing Major Assemblies 9 15 ...
Страница 284: ...A3 SYTFMD Figure 9 10 A3 SYTFMD Removal Replacement Replacing Major Assemblies 9 17 ...
Страница 286: ...A4 Input Attenuator Figure 9 11 A4 Input Attenuator Removal Replacement 1 of 2 Replacing Major Assemblies 9 19 ...
Страница 287: ...A4 Input Attenuator Figure 9 12 A4 Input Attenuator Removal Replacement 2 of 2 9 20 Replacing Major Assemblies ...
Страница 289: ...A5 VCO Sampler Figure 9 13 A5 VCO Sampler Removal Replacement 1 of 3 9 22 Replacing Major Assemblies ...
Страница 290: ...A5 VCO Sampler Figure 9 14 A5 VCO Sampler Removal Replacement 2 of 3 Replacing Major Assemblies 9 23 ...
Страница 291: ...A5 VCO Sampler Figure 9 15 A5 VCO Sampler Removal Replacement 3 of 3 9 24 Replacing Major Assemblies ...
Страница 294: ...A7 2nd Mixer Figure 9 17 A7 2nd Mixer Removal Replacement Replacing Major Assemblies 9 27 ...
Страница 298: ...A9 2nd Converter PLL Figure 9 19 A9 2nd Converter PLL Removal Replacement 1 of 2 Replacing Major Assemblies 9 31 ...
Страница 299: ...A9 2nd Converter PLL Figure 9 20 A9 2nd Converter PLL Removal Replacement 2 of 2 9 32 Replacing Major Assemblies ...
Страница 301: ...A10 Power Supply Driver Figure 9 21 A10 Power Supply Driver Removal Replacement 9 34 Replacing Major Assemblies ...
Страница 303: ...A11 Last Converter Figure 9 22 A11 Last Converter Removal Replacement 1 of 2 9 36 Replacing Major Assemblies ...
Страница 304: ...A11 Last Converter Figure 9 23 A11 Last Converter Removal Replacement 2 of 2 Replacing Major Assemblies 9 37 ...
Страница 309: ...A15 RF 1st Converter Figure 9 27 A15 RF 1st Converter Removal Replacement 9 42 Replacing Major Assemblies ...
Страница 311: ...A16 Low Pass Filter Figure 9 28 A16 Low Pass Filter Removal Replacement 9 44 Replacing Major Assemblies ...
Страница 313: ...A17 Low Pass Filter Figure 9 29 A17 Low Pass Filter Removal Replacement 9 46 Replacing Major Assemblies ...
Страница 329: ......