HP 8560A, Service Manual

Page: 104 / 450

19. 10 MHz Reference Adjustment (Option 003)
2. Set the frequency counter controls as follows:
3.
4.
FUNCTION/DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .FREQ A
INPUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A:
ATTN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OFF
AC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OFF (DC coupled)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .OFF (1 input impedance)
AUTO TRIG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ON
100 FILTER A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OFF
switch (rear panel) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . EXT
On the HP Frequency Counter, select a 1 second gate time by pressing
Offset th
1 e ayed frequency by -10.0 MHz by pressing
MATH The
frequency counter should now display the difference between the frequency of the INPUT A
signal and 10.0 MHz with a displayed resolution of 0.010 Hz (10
Locate the FREQ ADJ control on the HP 8560A. This control is accessible through the
center deck of the spectrum analyzer. See Figure 2-22.
5.
6.
Remove the dust cap screw.
Use a nonconductive adjustment tool to adjust the FREQ ADJ control on the A21 OCXO
for a frequency counter indication of 0.00 Hz.
7.
8.
9.
On the HP Frequency Counter, select a 10 second gate time by pressing
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
Wait at least 2 gate periods for the frequency counter to stabilize, and then adjust the
FREQ ADJ control on the A21 OCXO for a stable frequency counter indication of 0.000
fO.O1O Hz.
Replace the dust cap screw on the A21 OCXO.
2-70 Adjustment Procedures