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9.
If
the
lock detector is not properly phased,
every
peak will not be
of
equal amplitude (see example
below). Adjust
C24
until the
correct waveform
above
is
obtained.
If
the
correct waveform cannot
be
obtained, select
in test
a value
for
C12 that in
conjunction
with
the
adjustment
of
C24 will pro-
duce the correct
waveform.
VLD
(VOLTS)
.2
.1
.01
.02
.03
t
(seconds)
3.3.4.3 FM Deviation
1.
Select
Generate
FM function and Gen/Mon Mtr
display. Set
the generate
frequency to 100 MHz.
2.
Connect the calibrated
external
modulation meter
to
the Antenna port
on the front
panel. Tune the
external modulation
meter to 100-MHz FM.
3.
Turn on the Modulation 1 KHz Level
switch
and
adjust
for
a reading
of 20
kHz
on the CRT
gener-
ate-deviation display.
4.
Adjust R12
through the
hole in
the
RF
Synthe-
sizer
cover.
(First
locate R12 by removing the RF
Synthesizer
cover.) The
reading
should
be 20kHz
±
1 kHz,
as
measured by
the
external modulation
meter.
3.3.5 FREQUENCY STANDARD
3.3.5.1
Oven Ready Light
1.
Remove
System
Analyzer bottom
cover.
NOTE
If
the
System Analyzer
has
a tem-
perature
compensated crystal
oscillator
(TCXO)
perform
align-
ment 3.3.5.1.1
TCXO.
If the
sys-
tem
analyzer has an
oven controlled
crystal oscillator
(OCXO) perform
alignment
3.3.5.1.2
OCXO.
3-10
3.3.5.
1.1 TCXO.
1.
Turn
System Analyzer
ON.
2.
Turn
R8
(see
Figure
3-9) on
the
frequency
Stan-
dard Interface board fully clockwise which will
turn
the
oven
ready light
on the front
panel
ON.
3.3.5.1.2
ocxo.
1.
Turn System Analyzer on and wait
approximately
10-20 minutes until heater input
current and fre-
quency stabilize. To monitor the heater input
cur-
rent put
a
DVM
across
Rll
and
R12 (see Figure
3-
9)
which are
in
parallel. The warm-up current will
be
700
to 900
rnA
(voltage
across
Rll and R12
will
be
0.35 to
0.45 V de).
The stabilized current
will be
200
to 250
mA
(0.1 to 0.13 Vdc).
2.
Once the heater input has
stabilized, adjust R8 on
the frequency
Standard Interface board until the
oven
ready light on the
front
panel just turns
on.
3.
Connect an external resistor load from
the collec-
tor to Q1
to ground to
increase the heater
input
current
to 350 rnA (0.18 Vdc
across Rll and
R12).
The
typical
resistor
value
is
100
ohms,
2
watts. The
resistor
value
required to bring the heater input
current to 350
mA may
change
from unit to
unit.
4.
With
the
external load resistor
connect,
adjust R8
on
frequency Standard Interface board until the
oven
ready light
just
fully turns ON.
5.
Remove load resistor and make
sure oven
ready
light
is turned
ON.
3.3.5.2 Oscillator Level
1.
Connec'w a high
input impedance
scope
probe to the
junction
of C15
and
C17 on
the
frequency Stan-
dard Interface Board (see Figure 3-9).
2.
Adjust R18
on
the
frequency
Standard Interface
Board
for a
peak-to-peak
voltage
between
1
and
2
volts
at junction
ofC15 and C17.
3.3.5.3
Oscillator Frequency
1.
Connect
an
external
frequency
counter,
with at
least
a
1 part in 10
9
stability
reference oscillator,
to
the 10 MHz
STD output on the
system
analyz-
er's
back
panel.
2.
Remove
the
.time base
-
calibration cover
screw
on
the
lower
left
side of the System
Analyzer.
3.
Turn
on
System Analyzer and allow
to warm up.
Ten
minutes for a
TCXO
or
20
minutes
for
a
OCXO until
oven
ready light
comes on.
4.
Using
an
appropriate
non-metallic
tuning
tool,
adjust
the
timebase
oscillator
for
a counter
read-
ing
of
10
MHz ±
1
Hz.
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Table of Contents
Troubleshooting
