HP 8568B, Performance Tests And Adjustments Manual, Page: 211 / 313

12. Time Base Adjustment (SN and Below, also and Above)
6. Set the Frequency Counter controls as follows:
INPUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A
ATTENUATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DC Coupled
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OFF
1 input impedance . . . . . . . . . . . . . . . . . . . . . . . . . . OFF
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ON
100 FILTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OFF
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 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:
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:
Reading 8:
Reading 9:
Reading 10:
13. Position the spectrum analyzer on its right side as shown
in Figure 3-52 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.
Adjustments 3-97