HP 70908A, Руководство по обслуживанию

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T est 14. Miscellaneous Residual Responses
The purpose of this verication test is to measure residual responses generated by the DUT
with no signal applied to the DUT RF INPUT . (The residual responses measured are harmonics
of the 300 MHz reference input.)
This is a nal test.
1. Connect the equipment as shown in the test setup illustration for this procedure .
2. Set the mainframe line switch to ON.
3. Load and run T est 14. Miscellaneous Residual Responses . Refer to Chapter 2 for information
about running the software .
When performing this verication test, before measuring residual responses , the test
characterizes DUT gain, DUT input attenuator , and the calibrated spectrum analyzer input
attenuator . The characterization data later corrects the measured residual responses .
Characterizing the DUT Gain
The full microwave source provides a 300 MHz, 010 dBm , signal at the DUT RF INPUT . DUT
input attenuation is 10 dB. The local oscillator source tunes to center the response . The
calibrated spectrum analyzer stores the 21.4 MHz OUT amplitude and corrects it for DUT
atness . The test then calculates DUT gain, the corrected 21.4 MHz amplitude minus 10 dBm
RF INPUT .
Characterizing the DUT Input Attenuator
With the DUT input attenuator set to 10 dB attenuation, the calibrated spectrum analyzer
measures the 21.4 MHz OUT amplitude . The measurement repeats with 0 dB input attenuation.
The DUT attenuator correction factor equals the second measurement minus the rst. Only the
0 and 10 dB DUT input attenuator settings are of interest.
Characterizing the Calibrated Spectrum Analyzer Input Attenuator
With the calibrated spectrum analyzer input attenuator set to 10 dB, the calibrated spectrum
analyzer measures 21.4 MHz OUT amplitude of the DUT . The measurement repeats with 0 dB
attenuation. The calibrated spectrum analyzer attenuation correction factor equals the second
measurement minus the rst.
Measuring Residuals
The full microwave source RF output is o. The calibrated spectrum analyzer settings
are 050 dBm reference level, 100 Hz span, 30 Hz resolution bandwidth. The DUT input
attenuation is 0 dB. In 1H0 band only , the local oscillator source tunes in sequence to the
fundamental and the rst eight harmonics of 300 MHz, and the calibrated spectrum analyzer
measures responses at the 21.4 MHz OUT . The test corrects the measurements for DUT
gain, DUT attenuation error , calibrated spectrum analyzer error , and DUT atness , and then
compares the results with test limits .
8-30 Module V erication T ests