Chapter 4 133
RF Section Troubleshooting
Troubleshooting
Verifying the 22.5 MHz IF Signal
• Verify the input attenuator on the N9000A is set to 10 dB. Look near the top of
the display near the center and verify that
Atten: 10 dB is visible. If needed
change the input attenuator by pressing
AMPTD, Attenuation, 10 dB on the
analyzer.
• Referring to Figure 4-1, carefully disconnect the W4 cable at A8J320.
• Connect the W4 cable to the MMCX female to SMA female connector. Use an
appropriate cable to go from the SMA connector to the RF input of a
functioning spectrum analyzer to verify the 22.5 MHz I.F. and amplitude is
correct.
• Press
Freq, 22.5 MHz, Span, 1 MHz, Peak Search on the functioning spectrum
analyzer.
• The analyzer marker should read 22.5 MHz at −25 dBm ± 4 dBm as shown in
Figure 4-3.
Figure 4-3 A2 Analog I.F. Output
• If the 22.5 MHz signal is not measuring the correct power level, do not assume
the RF Assembly is the most probable cause until the 3rd L.O. frequency and
power level have been verified below.
NOTE You should hear a distinct snap when reconnecting the W4 cable. If this cable is
not installed properly, intermittent signal fluctuations may occur on the analyzer
display.
To Next Page
Loading...
