HP 70908A, Руководство по обслуживанию

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A djustment 27. 21.4 MHz IF Frequency Response
The purpose of this adjustment procedure is to measure the 3 dB bandwidth and the passband
frequency response of the 21.4 MHz OUT amplitude .
1. Set the mainframe line switch to OFF .
2. Remove the HP 70908A RF section from the mainframe .
3. Install the extender module in the mainframe and connect the HP 70908A RF section to the
extender cable .
4. Connect the equipment as shown in Figure 7-56.
5. Set the mainframe line switch to ON and allow at least 30 minutes initial warmup before
starting the adjustment.
6. Load and run A djustment 27. 21.4 MHz IF Frequency Response . Refer to Chapter 2 for
information about running the software .
When performing this adjustment, the measurement is made in the 1H0 and the 1L0 bands
with the full microwave source providing RF INPUT amplitudes of 300 MHz and 2.7 GHz,
respectively .
The local oscillator source frequency increments in 200 kHz steps , thus producing 15.4 to
27.6 MHz signals at the 21.4 MHz OUT . A power meter measures each step . The test determines
3 dB bandwidth by comparing power at 21.4 MHz with power at the step frequencies . With
the same power data, the test determines passband amplitude response from 18.9 MHz to
23.9 MHz.
Adjustment Procedures 7-65