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Downconverter Operation
Phase Noise Measurement <26.5 GHz System Control
•
Microwave/mm band: (
•
Auto/Manual Input Attenuation & IF Gain: Auto
•
Input Attenuation: determined by system if Auto is selected.
•
IF Gain: determined by system if Auto is selected.
•
Mixer Maximum Level: system enters factory default value, –5 dBm.
Tuning Sensitivity: select the sensitivity determined in step 1 (if the
HP 70427A is being tuned).
•
LO Power: system enters factory default value, +10 dbm.
•
Auto/Manual LO Frequency selection: Auto
•
LO Frequency: determined by the system.
•
100 MHz Ref. Chain PLL Bandwidth: use the default, 126 Hz.
•
600 MHz Ref. Chain PLL Bandwidth: use the default, 10 kHz*.
*Unless use of a wider bandwidth is dictated by the tuning sensitivity
and the HP 3048A PLL bandwidth (see step 1). The only reason to use
anything other than the default bandwidth is if the downconverter is
being tuned using 1.0 ppm/V tuning sensitivity and the HP 3048A
system bandwidth is greater than 10 kHz. If the downconverter is being
tuned, the 600 MHz PLL bandwidth must be wider than the HP 3048A
system bandwidth.
Step 3 - Start a new measurement
Connect the sources when the software pause at the connection diagram.
Set the reference source output as follows:
•
Frequency: Same as downconverter's IF.
•
Amplitude: +16 dBm
Step 4 - Autorange the downconverter
1. Press the
AUTO Range
This will trigger a one-time autoranging of the downconverter's input
attenuator and IF gain.
Step 5 - Verify beatnote and proceed
If the reference source is under user control tune it, if necessary, to get a
beatnote less than 5% of the peak tuning range. if the reference source is
under system control it will be tuned automatically.
3-24 HP 70427A/HP 70428A User's Guide
μ
−
W) 0
26.5
softkey of the HP 3048A controller.
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