
Source
Low
Band
Operation
The
low
band
frequency
range
is
300
kHz
to
16
MHz.
These
frequencies
are
generated
by
locking
the
A3
source
to
a
reference
signal.
The
reference
signal
is
synthesized
by
mixing
down
the
fundamental
output
of
the
fractional-N
V
CO
with
a
40
MHz
crystal
reference
signal.
Low
band
operation
diers
from
high
band
in
these
respects:
The
reference
frequency
for
the
A11
phase
lock
is
not
a
xed
1
MHz
signal,
but
varies
with
the
frequency
of
the
fractional-N
V
CO
signal.
The
sampler
diodes
are
biased
on
to
pass
the
signal
through
to
the
mixer
.
The
1st
IF
signal
from
the
A4
R
sampler
is
not
xed
but
is
identical
to
the
source
output
signal
and
sweeps
with
it.
The
following
steps
outline
the
low
band
sweep
sequence
,
illustrated
in
Figure
12-4.
1.
A
signal
(FN
LO)
is
generated
by
the
fractional-N
V
CO
.
The
V
CO
in
the
A14
fractional-N
assembly
generates
a
CW
or
swept
signal
that
is
4O
MHz
greater
than
the
start
frequency
.
The
signal
is
divided
down
to
1OO
kHz
and
phase
locked
in
the
A13
assembly
,
as
in
high
band
operation.
2.
The
fractional-N
V
CO
signal
is
mixed
with
40
MHz
to
produce
a
reference
signal.
The
signal
(FN
LO)
from
the
fractional-N
V
CO
goes
to
the
A12
reference
assembly
,
where
it
is
mixed
with
the
4O
MHz
V
CXO
(voltage
controlled
crystal
oscillator).
The
resulting
signal
is
the
reference
to
the
phase
comparator
in
the
A11
assembly
.
3.
The
A3
source
is
pretuned.
The
source
output
is
fed
to
the
A4
R
sampler/mixer
.
The
pretuned
D
A
C
in
the
A11
phase
lock
assembly
sets
the
A3
source
to
a
frequency
1
to
6
MHz
above
the
start
frequency
.
This
signal
(source
output)
is
applied
to
the
A4
R
sampler/mixer
assembly
via
the
coupled
arm
of
the
A30
dual
directional
coupler
.
4.
The
signal
from
the
source
is
fed
back
(1st
IF)
to
the
phase
comparator
.
The
source
output
signal
passes
directly
through
the
R
sampler
in
the
A4
assembly
,
because
the
sampler
is
biased
on.
The
signal
(1st
IF)
is
fed
back
unaltered
to
the
phase
comparator
in
the
A11
phase
lock
assembly
.
The
other
input
to
the
phase
comparator
is
the
heterodyned
reference
signal
from
the
A12
assembly
.
Any
frequency
dierence
between
these
two
signals
produces
a
proportional
error
voltage
.
5.
A
tuning
signal
(Y
O
DRIVE)
tunes
the
source
and
phase
lock
is
achieved.
The
error
voltage
is
used
to
drive
the
A3
source
YIG
oscillator
to
bring
the
YIG
closer
to
the
reference
frequency
.
The
loop
process
continues
until
the
source
frequency
and
the
reference
frequency
are
the
same
and
phase
lock
is
achieved.
12-16
Theory
of
Operation
Содержание 8752C
Страница 22: ...Before Applying Power 15 6 Servicing 15 6 Index Contents 16 ...
Страница 38: ......
Страница 43: ...Figure 2 1 Measurement Uncertainty Window System Veri cation and Performance Tests 2 5 ...
Страница 80: ...Figure 2 15 Magnitude Dynamic Accuracy Test Setup 2 42 System Veri cation and Performance Tests ...
Страница 116: ......
Страница 122: ...Figure 3 1 Location of Major Assemblies 3 6 Adjustments and Correction Constants ...
Страница 176: ......
Страница 192: ...4 16 Start Troubleshooting Here ...
Страница 193: ......
Страница 194: ...Figure 4 7 HP 8752C Overall Block Diagram 2 of 4 Option 003 and 004 Start Troubleshooting Here 4 19 ...
Страница 195: ...Figure 4 7 HP 8752C Overall Block Diagram 3 of 4 Option 006 4 20 Start Troubleshooting Here ...
Страница 196: ...Figure 4 7 HP 8752C Overall Block Diagram 4 of 4 Option 004 and 006 Start Troubleshooting Here 4 21 ...
Страница 197: ......
Страница 221: ...5 24 Power Supply Troubleshooting ...
Страница 222: ......
Страница 225: ...Digital Control Group Block Diagram Figure 6 1 Digital Control Group Block Diagram Digital Control Troubleshooting 6 3 ...
Страница 267: ...Figure 7 18 25 MHz HI OUT Waveform from A14J1 Figure 7 19 60 MHz HI OUT Waveform from A14J1 Source Troubleshooting 7 27 ...
Страница 271: ...Figure 7 21 A14 Generated Digital Control Signals Source Troubleshooting 7 31 ...
Страница 301: ...Figure 9 2 Typical Smith Chart Traces of Good Short a and Open b Accessories Troubleshooting 9 7 ...
Страница 302: ......
Страница 366: ......
Страница 378: ...Figure 11 4 Typical ED Re ection Test Port 11 12 Error Terms ...
Страница 380: ...Figure 11 5 Typical ES Re ection Test Port 11 14 Error Terms ...
Страница 382: ...Figure 11 6 Typical ER Re ection Test Port 11 16 Error Terms ...
Страница 384: ...Figure 11 7 Typical EX with 10 Hz Bandwidth Figure 11 8 Typical EX with 3 kHz Bandwidth 11 18 Error Terms ...
Страница 386: ...Figure 11 9 Typical ET 11 20 Error Terms ...
Страница 407: ...Figure 12 5 High Band Operation of the Source Theory of Operation 12 21 ...
Страница 410: ...Figure 12 6 Receiver Functional Group standard and Option 003 12 24 Theory of Operation ...
Страница 411: ...Figure 12 7 Receiver Functional Group Option 003 and 004 Theory of Operation 12 25 ...
Страница 412: ...Figure 12 8 Receiver Functional Group Option 006 12 26 Theory of Operation ...
Страница 413: ...Figure 12 9 Receiver Functional Group Option 004 and 006 Theory of Operation 12 27 ...
Страница 416: ......
Страница 419: ...Figure 13 1 Module Exchange Procedure Replaceable Parts 13 3 ...
Страница 423: ...Major Assemblies Replaceable Parts 13 7 ...
Страница 425: ...Front Panel Assemblies Replaceable Parts 13 9 ...
Страница 427: ...Rear Panel Assemblies Replaceable Parts 13 11 ...
Страница 429: ...Cables Top View Replaceable Parts 13 13 ...
Страница 431: ...Front Panel Cables and Attaching Hardware Replaceable Parts 13 15 ...
Страница 433: ...Rear Panel Cables and Attaching Hardware Replaceable Parts 13 17 ...
Страница 435: ...Source and Sampler Parts Standard and Option 003 Replaceable Parts 13 19 ...
Страница 437: ...Source and Sampler Parts Option 004 006 Replaceable Parts 13 21 ...
Страница 439: ...Source and Sampler Parts Options 004 and 003 004 Replaceable Parts 13 23 ...
Страница 441: ...Source and Sampler Parts Option 006 Replaceable Parts 13 25 ...
Страница 443: ...Display Bezel Assembly Replaceable Parts 13 27 ...
Страница 445: ...Chassis Parts Replaceable Parts 13 29 ...
Страница 447: ...Top View of Attaching Hardware and Post Regulator Fuses Replaceable Parts 13 31 ...
Страница 449: ...Bottom View of Attaching Hardware Replaceable Parts 13 33 ...
Страница 488: ......