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Models 8672S/86720A
Performance Tests
SIGNAL GENERATOR SYSTEM OPERATIONAL VERIFICATION TEST (cont'd)
Procedure
Pulse Modulation Check
(cont'd)
8. Set the Signal Generator System to 0 dBm as displayed on the power meter and
press the CW/PULSE and _TL / 1_T keys. Power output should not change by
more than 1 dB from the level set in CW.
9. Set the Signal Generator System to 10 GHz. Typically power output should not
'
change by more than 6 dB from low band operation.
10. Set the Signal Generator System to 1 GHz at 0 dBm (with 0 dB on vernier). Attach
spectrum analyzer to the FEU in place of the power meter. See Figure 4-2. Tune in
the signal and set it to the top graticule line on the spectrum analyzer. Adjust
spectrum analzyer bandwidth to get a noise floor on the spectrum analyzer at least
70 dB below the signal level. Use 20 dB of input attenuation on the spectrum
analyzer.
11. Change the FEU to pulse _TL mode. The output level should drop by at least 80 dB.
Remove all input attenuation and attempt to find the reduced signal. The signal, if
visible should be at least 60 dB below the top graticule line on the spectrum
analyzer with the input attenuation removed.
12. Attach diode detector to the FEU's .01 TO 18.0 GHz OUTPUT connector. Attach
output of the detector to oscilloscope Channel A input. Set oscilloscope impedence
on Channel A to 50 ohms. Connect pulse generator output to the FEU PULSE
INPUT. Connect pulse generator trigger output to oscilloscope trigger input and set
oscilloscope for external trigger. Use a sweep speed of 20 ns per division on the
oscilloscope. See Figure 4-2.
SIGNAL GENERATOR
SPECTRUM
SYSTEM
Figure 4-2. Pulse Modulation Test Setup
13. Set pulse generator for 100 ns wide pulse, minimum delay with rate fast enough to
get a bright display on the oscilloscope. Measure the rise and fall times on the
detected pulse from the 10% to the 90% points. The rise and fall times should be less
than 15 ns.
Phase Lock Check
14. Remove 100 MHz cable on back of the FEU. The RF UNLOCK lamp should light.
Reconnect the cable.
4-5
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