Giga-tronics GT 9000, Operation & Maintenance Manual

Page: 117 / 238

4.2.12 Pulse Modulation Accuracy Test
Specification
Leveled Pulsed Output Power
(referenced to leveled,
unmodulated output power): +.5 dB, typical (> 100 ns pulse width)
+1 dB, typical (< 100 ns pulse width)
Procedure
1. Connect the equipment as shown in the figure. The oscilloscope input impedance should
be 50
Ω
. Allow 20 minutes warm-up.
2. Press [SHIFT] [RESET] on the UUT and set the frequency to the first Test Data Sheet
frequency which is within the operating range of the instrument.
3. Set the oscilloscope to 5 mv/div and using the vertical position of the oscilloscope,
adjust the trace to the centerline of the screen. Change the level setting of the UUT by
plus and minus 1 dB and note the trace position on the screen. Return to 0 dBm.
4. Enable the pulse modulation of the UUT by pressing [PM] [MODE..(INT)]
[SCROLL..(RATE)] [200] [kHz] [SCROLL..(WIDTH)] [.1] [US] [ON].
5. Measure and record the difference between the CW reference level and the negative
peak of the pulse.
6. Change the pulse width to 50 ns and again measure and record the difference between
the CW reference level and the negative peak of the pulse.
7. Repeat steps 3 to 6 for each Test Data Sheet frequency which is within the operating
range of the instrument.
Equipment Required
Oscilloscope
Crystal detector
Figure 4-8. Pulse Modulation Accuracy Test
Calibration and Testing
Manual No. 120AM00250, Rev C, September 1998
4-23