Keysight Technologies N9040B UXA Signal Analyzer Service Guide 155
RF Section Troubleshooting (RF/Microwave Analyzers)
Troubleshooting
To verify the electronic attenuator operation on instruments with Option EA3,
set up the analyzer to view the 50 MHz calibrator signal on screen. Press
Input/Output, RF Calibrator, 50 MHz, FREQ (Channel), Center Frequency,
50 MHz, Span, 500 kHz
Press Peak Search to place a marker on the calibrator signal, then press
Marker Delta
Activate the electronic attenuator. Press AMPTD, Attenuation, Elec Atten,
Enabled.
Press the up arrow key to step through all attenuator steps while monitoring
the marker delta readout. The signal level should not change more than 0.4 dB
as indicated by the marker delta readout.
If the attenuator switches slowly, or the signal is not present when the
electronic attenuator is switched into the signal path or the signal appears only
when the attenuator is switched on, suspect the control signals from the A15
Front End Controller are faulty or the A13 Front End assembly is faulty. If the
attenuator switches, but the switching error between attenuator settings is
greater than ± 0.4 dB, assure that any other internal alignment failures are
resolved since the System Gain alignment must run before optimum
performance is possible. Assure you have evaluated all causes before you
replace the Front End assembly.
If you determine the problem is at a frequency other than 50 MHz, perform the
low band flatness adjustment before replacing the Front End assembly.
To Next Page
Loading...
Need help?
General
