HP 70427A User Manual page 113

Downconverter Operation
AM Noise Measurement (Input AM Detector) User Control
When the input AM detector is enabled the signal is routed through the
downconverter's input attenuator and to the AM detector. The detector's
output is routed to AM NOISE output.
The downconverter's mixer is not in the signal path.
Step 3 - Define the measurement
Follow the instructions in the HP 3048A manual along with the following
information:
1. Specify Measurement Type and Frequency Range
•
Measurement Type: AM Noise.
2. Enter Source and Interface Parameters
•
Carrier Frequency: DUT frequency.
•
Detector/Discr. Input Frequency: DUT frequency.
•
Detector - External Phase / AM Detector.
3. Specify a Calibration Process
•
Phase Detector Constant: Derive from Double Sided Spur
•
Spur Amplitude: – 26 dBc
•
Spur Frequency: 1kHz
4. Specify the Control of Signal Sources
•
CAL sources: USERS DEVICE, MANUAL CONTROL
Step 4 - Begin a new measurement
When the HP 3048A software pauses at the system connect diagram,
connect the DUT to the downconverter's SIGNAL input and make any other
connections shown that haven't been done yet. The filter shown on the
connect diagram is not needed because the HP 70427A has a filter in it.
Step 5 - Set the DUT power to +10 dBm
The downconverter's AM detector is specified at an input level of +10 dBm,
but it will work with input levels as low as 0 dBm.
Step 6 - Autorange the downconverter
1. Press the
AUTO ATTEN
2. Press the
AUTO RANGE
This triggers a one-time autoranging of the downconverter's input attenuator.
3-14 HP 70427A/HP 70428A User's Guide
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