Agilent Technologies 856290216 service manual Off

11.10 MHz Reference Adjustment-OCXO (Non-Option 103)

b. Allow the spectrum analyzer to remain powered on continuously for at least 24 hours to ensure that the A21 OCXO temperature and frequency stabilize.

Note	If the reference is set to 10 MHz EXT , press 10 MHz INT . Allow the 24 hour
	warmup for the OCXO before continuing. When the 10 MHz reference is set
	to 10 MHz EXT , the OCXO is not operating or warmed up.

c. Connect the frequency standard to the frequency counter rear panel TIMEBASE IN/OUT connector.

d. Connect a BNC cable between the spectrum analyzer rear panel 10 MHz REF IN/OUT connector and INPUT A on the frequency counter.

2. Set the frequency counter controls as follows:

Function/data	. .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FREQ A
Input A:
XlOAttenuator		OFF
A C	. .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . O F F ( D C c o u p l e d )
50 %Z	.	, . . . . . . . . . . . . . . . . . . . . . OFF (1 MR input impedance)
AutoTrigger		ON
100 kHz filter A	, . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OFF
INT/EXT switch (rear panel)		. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . EXT

3.Select a 1 second gate time on the HP 5334A/B frequency counter by pressing ( G A T E ] , 1 , [ T I M E ) .

4.To offset the displayed frequency by -10.0 MHz, press MATH (SELECT/ENTER), (CHX/EEX), 10, (CHS/EEX), 6, (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).

5.Locate the FREQ ADJ control on the spectrum analyzer. This control is accessible through the center deck of the spectrum analyzer. See Figure 2-19.

6.Remove the dust-cap screw.

7.Use a nonconductive adjustment tool to adjust the FREQ ADJ control on the A21 OCXO for a frequency counter reading of 0.00 Hz.

8.On the HP 5334A/B frequency counter, select a lo-second gate time by pressing [-TIME), 10, (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).

9.Wait at least two gate periods for the frequency counter to stabilize, then adjust the FREQ ADJ control on A21 OCXO for a stable frequency counter reading of 0.000 Hz kO.010 Hz.

10.Replace the dust-cap screw to A21 OCXO.

2-50 Adjustment Procedures