HP 70427A User Manual page 111

NOTE
Downconverter Operation
Millimeter Phase Noise Measurement - User Control
c. Adjust the bias level with the knob, Up/Down keys, or enter a power
with the numeric keypad.
Adjust the mixer LO power for maximum IF signal measured on the
spectrum analyzer.
a. Press the
LO POWER
b. Adjust the LO power with the knob, Up/Down keys, or enter a
power with the numeric keypad.
Repeat the steps above for maximum IF output measured on the RF
spectrum analyzer.
This completes the mixer bias adjustment.
5. Autorange the downconverter's IF gain as follows:
a. Press the
Amplitudes
b. Press the
AUTO RANGE
Step 11 - Verify the beatnote and proceed
If the reference source is under the user control, adjust its frequency if
necessary to get a beatnote less than 5% of peak tuning range. If the
reference source is under system control it will be tuned automatically.
After the beatnote is within the limits the system asks for, proceed with the
measurement.
When the downconverter is configured for mm operation don't apply a
high-level microwave signal to the input. Change the mode back to
press the
INSTR PRESET
3-12 HP 70427A/HP 70428A User's Guide
softkey.
softkey
softkey.
key. This will protect the IF amplifier from damage.
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