Agilent Technologies 8564EC, Service Manual

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128 Chapter 3
Manual Adjustment Procedures
4 . Sampling Oscillator Adjustment
Sampler Match Adjustment
1. Connect the negative DVM test lead to A15J400 pin 6, and the
positive DVM test lead to A15J400 pin 1.
2. Press
FREQUENCY
and set the spectrum analyzer center frequency
to 2302.3 MHz. This sets the sampling oscillator to 291.667 MHz.
3. Adjust A15C100 SMPL MATCH to peak the voltage displayed on the
DVM.
4. Record the displayed voltage in Table 3-9 on page 128 as the
displayed voltage for the sampling oscillator frequency of
291.667 MHz.
5. Press
FREQUENCY
on the spectrum analyzer. Use the keypad to set
the spectrum analyzer center frequency to the frequencies listed in
Table 3-9 on page 128 . At each listed frequency, record the displayed
voltage in the table.
6. If the difference between the maximum and minimum voltages is
less than 0.50 V, and all voltage readings are b0.5 and
+2.5 Vdc, proceed to step 15.
7. Locate the center frequency at which the voltage is lowest. Use the
keypad to set the spectrum analyzer to this frequency.
8. Readjust SMPL MATCH to set the displayed voltage to 0.8
±
0.1 Vdc.
9. Set the spectrum analyzer center frequency to 2302.3 MHz and
repeat steps 9 through 13.
10.Move the positive DVM test lead to A15J400 pin 3. Check that the
measured voltage is the negative of the voltage at pin 1, within
±
0.1 Vdc.
11.Disconnect the DVM probes from A15J400.
Table 3-9 Sampling Adjustments
Center
Frequency
(MHz) Sampling
Oscillator
(MHz) Displayed Voltage (Vdc)
1st Trial 2nd Trial 3rd Trial 4th Trial 5th Trial
2156.3 285.000
2176.3 286.364
2230.3 288.462
2263.3 290.000
2302.3 291.667
2158.3 293.478