
12. Time Base Adjustment (SN
to
The
10 MHz Quartz Crystal Oscillator (HP P/N 1081
11)
typically reaches its specified aging rate again within 72 hours after
being switched off for a period of up to 30 days, and within 24 hours
after being switched off for a period less than 24 hours. If extreme
environmental conditions were encountered during storage or
shipment (i.e. mechanical shock, temperature extremes)
the
oscillator
could require up to 30 days to achieve its specified aging rate.
Replacement oscillators are factory-adjusted after a complete warmup
and after the specified aging rate has been achieved. Readjustment
should typically not be necessary after oscillator replacement, and is
generally not recommended.
1. Set the rear-panel FREQ REFERENCE switch on
the
spectrum
analyzer RF Section to INT.
Note
The + 22 Vdc STANDBY supply provides power to the heater circuit in
the
10 MHz Frequency Standard assembly whenever line power
is applied to the RF Section. This allows the
10 MHz Frequency
Standard
oven
to remain at thermal equilibrium, minimizing
frequency drift due to temperature variations. The OVEN COLD
message
should typically appear on
the
spectrum analyzer display for
10 minutes or less after line power is first applied to the RF Section.
Note
The rear-panel FREQ REFERENCE switch enables or disables the RF
Section
Vdc switched supply, which powers the oscillator circuits
in the
10 MHz Frequency Standard. This switch must be set to
INT and the spectrum analyzer must be switched ON continuously
(not in STANDBY) for at least 72 hours before adjusting the frequency
of
the
10 MHz Frequency Standard.
2. Set the LINE switch to ON. Leave the spectrum analyzer ON
(not in STANDBY) and undisturbed for at least 48 hours to allow
the temperature and frequency of the
10 MHz Frequency
Standard to stabilize.
3. Press
TRACE B
(
CLEAR
-
WRITE
)
to turn off
the
display. This
prolongs CRT life while the spectrum analyzer is unattended. To
turn the CRT back on press
TRACE B (MAX HOLD)
4. Connect the (Cesium Beam) Frequency Standard to the Frequency
Counter’s rear-panel
IN/OUT connector as shown in
Figure 3-54.
5. Disconnect the short jumper cable on the RF Section rear panel
from the FREQ REFERENCE INT connector. Connect this output
(FREQ REFERENCE INT) to INPUT A on the Frequency Counter.
A REF UNLOCK message should appear on the CRT display.
6. Set the Frequency Counter controls as follows:
INPUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A
ATTENUATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DC Coupled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OFF
1
input impedance
. . . . . . . . . . . . . . . . . . . . . . . . . . OFF
AUTO TRIG . . . . . . . . . . . . . . . . . . . . . . .
ON
100
FILTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OFF
Adjustments
Содержание 8568B
Страница 13: ...6 7 IF Section Bottom View 6 10 Contents 7 ...
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Страница 54: ...9 RF Gain Uncertainty Test h I 1 I I I Figure 2 16 RF Gain Uncertainty Measurement 2 32 Performance Tests ...
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Страница 100: ...Test 9 RF Gain Uncertainty Test Step 6 2nd LO Shift Min Measured Max 1 0 dB 1 0 dB 2 78 Performance Tests ...
Страница 106: ...Test 13 Average Noise Level Test 2 84 Performance Tests ...
Страница 109: ...Test 16 Residual FM Test Test 16 Residual FM Test Step 14 Residual FM IMinIMeasuredIrax Performance Tests 2 87 ...
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Страница 307: ...w43 c c5 c4 c3 c2 Figure 6 l RF Section Top View A26 6 4 Major Assembly and Component locations ...
Страница 312: ...AlVl Figure 6 6 IF Section Front View w3 w9 Major Assembly and Component locations 6 9 ...