6. Sampling Oscillator Adjustment

12.Record the displayed voltage in Table 2-11 as the displayed voltage for the sampling oscillator frequency of 288 MHz.

13.Press (m) on the HP 8560A. Use the step keys to set the analyzer center frequency to the frequencies listed in Table 2-11. At each listed frequency, record the

displayed voltage in the table.

’

14.If the difference between the maximum and minimum voltages is less than 0.50 V, and all voltage readings are between to.5 and t2.5 Vdc, proceed to step 19.

15.Locate the center frequency at which the voltage is lowest. Use the II] and II] keys to set the HP 8560A to this frequency.

16.Readjust SMPL MATCH 1 to set the displayed voltage to 0.8 $0.1 Vdc.

17.Move the positive DVM test lead to A15J400 pin 3.

18.Set the HP 8560A center frequency to 511 MHz.

19.Readjust A15R237 SMPL PWR ADJ if necessary, until the voltage at A15J400 pin 3 is -0.5 to -2.5 Vdc and the voltage at A15J400 pin 1 is -0.5 to i-2.5 Vdc.

20.Disconnect the DVM probes from A15J400.

 

Coarse-Tune Adjustment

 

 

Note

This adjustment should be necessary only if the coaxial resonator 2200 has

 

been replaced or if there was insufficient range in the Sampling Oscillator

 

Fine-Tune Adjustment.

 

 

 

FREQUENCY

 

COUNTER

POWER

 

SUPPLY

SPECTRUM

 

A 1 4

ANALYZER

S K 1 8

Figure 2-9. Coarse-Tune Adjustment Setup

21.Set the HP 8560A m switch off and remove the top shield over the sampling oscillator. Connect the equipment as shown in Figure 2-9.

22.Remove any existing shorts from the exposed center-conductor of coaxial resonator 2200 to the ground plane.

Adjustment Procedures 2-35