Giga-tronics Series 12000A, Руководство по эксплуатации

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Performance Verification
Publication 31231, Rev. J, October 2003 4-21
4.4.5 Pulse Modulation Overshoot & Settling Time
4.4.5.1 Description
A crystal detector is connected to the 12000A, terminated in 50
Ω
and monitored with an oscilloscope.
4.4.5.2 Equipment Required
UUT
²
Oscillator
²
Pulse Generator
²
Crystal Detector
²
Coaxial Cable
4.4.5.3 Procedure
1. Connect the equipment as shown in Figure 4-10. The cable from the detector to the
oscilloscope should be kept as short as possible.
2. Press
[PRESET]
on the 12000A and set the frequency to the first test data sheet frequency
within the operating range of the instrument.
3. Enable external pulse modulation (at a 1 MHz rate and 0.5 ms width) on the 12000A. Press
[PULSE]
and use the softkey to turn on pulse modulation.
4. Set the oscilloscope to 5 mv/div and using the RF Level control of the 12000A and the vertical
position of the oscilloscope, adjust the peak to peak oscilloscope display to be from the top of
the screen (pulse off) to 2 divisions below the center line (pulse on). Adjust the oscilloscope
sweep time to 50 ns/div. Change the level setting of the 12000A by plus and minus 1 dB and
note the graticule position of the pulse on level. Return to the original value. Measure and
record the time for the pulse to be within 1 dB of its final value.
5. Change the level setting of the 12000A by plus and minus 2 dB and note the graticule position
of the pulse on level. Return to the original level. Measure and record any undershoot/
overshoot of the signal.
6. Repeat Steps 4 and 5 for each of the test data sheet frequencies within the operating range of
the instrument.
NOTE:
It is very important to use either the specified detector or one with similar rise
time characteristics. Even when terminated in 50
Ω
with a short cable, the detector
parameters can markedly influence the measurement.
Figure 4-10: PM Overshoot and Setting Time
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