Troubleshooting
the
A1
Leveling
Amplier
P
ower
Detector
The
power-sensing
detector
has
positive
detection
with
negative
bias
for
increased
sensitivity
.
T
o
verify
the
operation
of
the
detector
,
monitor
the
A1
DET
pin
with
a
DVM
(digital
voltmeter).
Remove
the
LO
input
cable
from
the
rear
panel
of
the
module
while
observing
the
voltage
.
The
voltage
should
go
more
negative
when
the
LO
power
is
removed.
The
detected
power
out
is
sent
to
the
A13
ALC/bias,
where
the
dierence
between
the
reference
and
the
detected
output
is
integrated.
The
integrated
output
is
sent
back
to
the
A1
leveling
amplier
A
TTEN
input.
As
LO
input
power
to
the
A1
increases
,
pin
2
drive
linearly
decreases
until
A13Q9
is
biased
o.
This
leaves
a
constant
current
that
is
proportional
to
maximum
attenuation
through
PIN
diode
2.
PIN
diode
1
responds
to
the
smaller
input
power
changes
.
Refer
to
A13
ALC/bias
troubleshooting
for
verifying
the
leveling
loop-drive
circuitry
.
LO
Harmonics
The
A1
leveling
amplier
also
provides
the
rear
panel
3
to
6.6
GHz
LO
output
that
is
unleveled
at
+5
to
10
dBm .
Harmonics
of
the
LO
signal
to
the
A3
SYTFMD
or
to
the
A15
RF
1st
converter
should
be
less
than
025
dBc
.
Harmonics
of
the
rear
panel
3
to
6.6
GHz
LO
signal
should
be
less
than
020
dBc.
Filter
Drive
W
aveform
The
lter
drive
comes
from
the
A10
power
supply/driver
.
T
o
observe
the
lter
drive
waveform,
place
the
module
on
an
HP
70001-60013
extender
module
and
make
all
connections
needed
for
spectrum
analyzer
operation.
P
erform
the
following
steps:
1.
On
the
HP
70000
Series
modular
spectrum
analyzer
system,
initiate
an
instrument
preset
and
set
the
controls
as
follows:
Span
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0
Hz
(press
NNNNNNNNNNNNNN
SPAN
,
0
NNNNNNNN
Hz
)
P
athlock
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ON
(press
4
MENU
5 ,
NNNNNNNNNNNNNNNNNNNN
config
,
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
PATHLOK
ON
)
LO
ST
ART
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3
GHz
(press
4
MENU
5 ,
NNNNNNNNNNNNNN
Freq
,
NNNNNNNNNNNNNNNNN
START
,
3
NNNNNNNNNNN
GHz
)
LO
STOP
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6.6
GHz
(press
NNNNNNNNNNNNNN
STOP
,
6.6
NNNNNNNNNNN
GHz
)
Sweep
time
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5
s
(press
4
MENU
5 ,
NNNNNNNNNNNNNNNNNNNN
BW,Swp
,
NNNNNNNNNNNNNNNNNNNNNNN
SWPTIME
,
5
NNNNN
s
)
2.
Set
an
oscilloscope
to
the
following
settings:
Display
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A
vs
B
mode
Channel
A
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0.5
V/Div
(with
10:1
Probe)
Channel
B
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0.1
V/Div
(with
10:1
Probe)
3.
Connect
channel
A
on
the
oscilloscope
to
the
VTF
pin
on
the
A1
leveling
amplier
.
Connect
channel
B
to
the
rear
panel
SWP
jack
of
the
HP
70900A/B
local
oscillator
source
.
A
djust
the
horizontal
position
of
the
the
oscilloscope
to
place
the
start
of
the
trace
at
the
left-most
graticule
.
A
djust
the
position
of
channel
so
that
0
V
is
one
division
above
the
bottom
of
the
CRT
.
4.
The
lter
drive
waveform
should
look
like
Figure
4-2,
with
the
horizontal
axis
corresponding
to
the
LO
frequency
and
the
vertical
axis
to
waveform
amplitude
.
F
or
an
HP
70900A/B
local
oscillator
source
sweep
of
3.0214
to
6.5214
GHz
the
waveform
should
have
a
squared
response
approximately
+6
V
to
+26
V
,
remaining
at
+26
V
for
the
remainder
of
the
sweep
.
If
there
is
a
problem
with
the
lter
drive
,
refer
to
A10
power
supply/driver
troubleshooting.
4-26
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: ......
Страница 61: ......
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 ...
Страница 125: ......
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: ......
Страница 205: ......
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: ......