19.10 MHz Reference Adjustment (Option 003)

2.Set the frequency counter controls as follows:

FUNCTION/DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .FREQ A INPUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A:

X10 ATTN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OFF AC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OFF (DC coupled) 5002 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .OFF (1 MR input impedance)

AUTO TRIG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ON 100 kHz FILTER A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OFF INT/EXT switch (rear panel) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . EXT

3.On the HP 5334A/B Frequency Counter, select a 1 second gate time by pressing IGATE (iJ 1[GATE). Offset th e d’rsp ayed frequency by -10.0 MHz by pressing

MATH [SELECT/ENTER) [CHX/EEX) Ilo) ICHS/EEX) @ (SELECT/ENTER) (SELECT/ENTER). 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 mHz).

4.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.Remove the dust cap screw.

6.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.On the HP 5334A/B Frequency Counter, select a 10 second gate time by pressing (GATE] Ilo] (GATE]. 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 mHz).

8.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.

9.Replace the dust cap screw on the A21 OCXO.

2-70 Adjustment Procedures