Troubleshooting A Low Band Problem - Keysight Technologies X Series Service Manual

RF Section Troubleshooting (Millimeter-Wave Analyzers)
Troubleshooting

Troubleshooting a Low Band Problem

Refer to the RF Lowband Path Block Diagram (Millimeter-Wave Analyzers) in
Chapter
internal 50 MHz, −25 dBm calibrator signal press Input/Output, RF Calibrator,
50 MHz.
The Low Band signal path (sometimes referred to as Band 0) is used for all
signals less than 3.6 GHz when the analyzer is used in normal operation. If the
stop frequency is set to 3.6 GHz, the analyzer displays only the Low Band
signal path. If the analyzer stop frequency is set above 3.6 GHz and the start
frequency is set below 3.6 GHz, the analyzer will sweep up to 3.6 GHz in low
band and then automatically switch to the high band path above 3.6 GHz.
A11 Low Band Switch Verification
Disconnect W3 from A13J2. See
right angle SMA adapter to W3 and measure the output of the Low Band
Switch with a spectrum analyzer. Expected signal is 50 MHz at −35.3 dBm
since the Low Band Switch has a few tenths of a dB loss.
If the signal level is incorrect, remove A10 Input Attenuator B output cable and
measure the output power. Expected signal is 50 MHz at −35 dBm. If the
attenuator output signal is correct but the Low Band output at W3 is incorrect,
suspect the A11 Low Band Switch, the interconnect cables, or the control
signals. The control signals are explained in
Troubleshooting", on page
Keysight N9010A EXA Service Guide
12and follow the instructions in the settings box. To enable the
233.
Figure 5-3 for location of connector. Attach a
Chapter 6, "Front End Control
213