12. 10
Standard Adjustment (SN 2637A and Below)
14. Remove the two adjustment cover screws from the A22 10 MHz
Frequency Standard. Refer to Figure 3-53 for the location of the
A22 10 MHz Frequency Standard.
Do not use a
adjustment tool to tune an oven-controlled
crystal oscillator (OCXO). The
will conduct heat away from the
oscillator circuit, shifting the operating conditions.
A 2 2
1 0 M H z
Figure 3-53. Location of 10 MHz Standard Adjustments
15. Use a nonconductive adjustment tool to adjust the
FINE
frequency adjustment on the A22 10 MHz Frequency Standard for
a Frequency Counter indication of 0.00 Hz. If the FINE frequency
adjustment has insufficient range, center the adjustment and
then adjust the COARSE frequency adjustment for a Frequency
Counter indication of 0.00 Hz.
16. On the Frequency Counter, select a 10 second gate time by
pressing
10
The Frequency Counter
should now display the difference between the frequency of the
INPUT A signal and 10.0 MHz with a resolution of 0.001 Hz (1
17. Wait at least 2 gate periods for the Frequency Counter to settle,
and then adjust the 16-turn FINE adjustment on the A22 10 MHz
Frequency Standard for a stable Frequency Counter indication of
(0.000 + Frequency Correction Factor)
Hz.
18. Replace the two adjustment cover screws on
the
A22 10 MHz
Frequency Standard.
19. Replace
the
RF Section bottom cover and reconnect the short
jumper cable between the FREQ REFERENCE INT and EXT
connectors.
Adjustments 3-107
