HP 8568B, Руководство по испытаниям и регулировке работы, Страница: 215 / 313

12. Time Base Adjustment (SN to
INT/EXT switch (rear panel) . . . . . . . . . . . . . . . . . . . . . EXT
7. On the Frequency Counter, select a 10 second gate time by
pressing, 10
8. Offset the displayed frequency by -10.0 MHz by pressing,
MATH
(
SELECT
/
ENTER
]
10
6
(
SELECT
/
ENTER
).
The Frequency Counter should now display the
difference between the frequency of the INPUT A signal
10 MHz Frequency Standard) and 10.0 MHz with a displayed
resolution of 1 (0.001 Hz).
9. Wait at least two gate periods for the Frequency Counter to settle,
and record the frequency of the 10 MHz Frequency Standard
as reading
Reading 1:
Note
The Quartz Crystal Oscillator has a typical adjustment range of
10 MHz Hz. The oscillator frequency should be within this range
after 48 hours of continuous operation.
10. Allow the spectrum analyzer to remain powered (not in
STANDBY) and undisturbed for an additional 24 hours.
11. Repeat steps 3 through 7 and record the frequency of the 10
MHz Frequency Standard as reading
Reading 2:
12. If
the
difference between reading and reading is greater
than 1
the
10 MHz Frequency Standard has not
achieved its specified aging rate; the spectrum analyzer should
remain powered (not in STANDBY) and undisturbed for an
additional
interval. Then, repeat steps 3 through 7,
recording
the
frequency of the 10 MHz Frequency Standard at the
end of each interval, until the specified aging rate of 1
mHz/day is achieved.
Reading 3:
Reading 4:
Reading 5:
Reading 6:
Reading 7:
13. Position the spectrum analyzer on its right side as shown
in Figure 3-54 and remove the bottom cover. Typically, the
frequency of the
10 MHz Frequency Standard will shift
slightly when the spectrum analyzer is reoriented. Record this
shifted frequency of the
10 MHz Frequency Standard.
Reading 8:
14. Subtract the shifted frequency reading in step 8 from the last
recorded frequency in step 7. This gives the frequency correction
factor needed to adjust the
10 MHz Frequency Standard.
Frequency Correction Factor:
Adjustments