Troubleshooting
the
A10
P
ower
Supply/Driver
BLOCK
G
sums
the
output
of
block
D
with
correction
information
from
the
following
sources:
(1)
hysteresis
from
block
F
and
the
discriminator
,
(2)
linearity
breakpoint
information
from
block
L,
and
(3)
dc
oset
information
from
block
M.
BLOCK
F
responds
only
to
the
fast
change
in
voltage
of
the
Tune
+
Span
signal
during
retrace
.
The
faster
the
rate
of
change
the
deeper
into
saturation
U5A
and
U5B
go
,
causing
the
duty
cycle
of
the
output
pulse
to
change
.
U6C
and
U6D
change
the
gain
of
U5A
depending
on
which
frequency
band
the
A3
SYTFMD
is
tuned
to
.
BLOCK
M
provides
a
dc
oset
proportional
to
321.4
MHz
to
the
A3
SYTFMD .
This
causes
the
YTF
to
track
321.4
MHz
below
the
LO
input
frequency
.
BLOCK
R
provides
an
oset-coil
summing
node
which
adds
together
a
squared
oset
error
correction
from
block
L
and
a
slope
correction
to
provide
linearization
of
the
oset
coil
response
.
This
is
added
to
a
dc
oset
proportional
to
321.4
MHz
(the
dierence
in
frequency
between
the
LO
input
of
the
A3
SYTFMD
and
YTF).
BLOCK
S
uses
the
signal
from
block
R
to
drive
current
in
the
discriminator
oset
coil
of
the
A3
SYTFMD .
BLOCKS
K
and
N
buer
the
output
from
the
A3
SYTFMD
and
provide
frequency-dependent
closed-loop
gain.
BLOCK
V
controls
the
A3
SYTFMD
temperature
by
reacting
to
temperature-sensing
information
and
changing
its
heater
current.
BLOCKS
O
and
A
shorten
lock-acquisition
time
.
The
search
oscillator
is
enabled
when
the
discriminator
loop
is
unlocked.
BLOCK
P
integrates
the
discriminator
frequency-error
information.
The
output
is
applied
to
the
YTF
main
coil
to
force
a
321.4
MHz
frequency
dierence
between
the
LO
input
of
the
A3
SYTFMD
and
YTF
.
BLOCKS
A,
I,
and
X
provide
the
A12
controller
with
the
following
status
information:
Circuit
Conditions
Reported
A1
LO
Leveling
Amplier
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
leveled/unleveled
A2
LO
Multiplier
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
leveled/unleveled
Discriminator
Lock
Loop
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
locked/unlocked
Tune
+
Span
Signal
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
present/not
present
BLOCK
T
drives
the
lter
switch
of
the
A2
LO
multiplier .
The
lter
is
on
for
HP
70900A/B
local
oscillator
source
frequencies
from
3
to
4.0
GHz.
BLOCK
U
drives
the
lter
of
the
A1
leveling
amplier
.
The
circuit
uses
the
Tune
+
Span
signal
to
reference
the
lter
drive
.
The
lter
reduces
in-band
harmonics
when
the
HP
70900A/B
local
oscillator
source
is
tuned
between
3
to
3.3
GHz
.
Driver
Troubleshooting
The
following
seven
procedures
are
provided
for
troubleshooting
driver
circuits:
Main
Coil
Drive
Loop
Gain
versus
Frequency
Hysteresis
and
Delay
Linearity
Compensation
A1
LOLA
Filter
Drive
Multiplier
V
oltage-Tuned
Filter
Drive
Interface
Block
T
roubleshooting
4-39
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: ......