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Test
Procedure
The following procedure lets you measure the video
feedthrough that occurs during pulse modulation.
1. Set up the 682XXB/683XXB as follows:
a.
Reset the instrument by pressing SYSTEM ,
then Reset . Upon reset, the CW Menu is dis
-
played.
b. Press Edit F1 to open the current frequency
parameter for editing.
c. Set F1 to 5.0 GHz.
d.
Press Edit L1 to open the current power level
parameter for editing.
e. Set L1 to the maximum leveled output power
level for the instrument being tested (refer to
Table 3-2, page 3-6).
f.
Press MODULATION , then Pulse . The Inter-
nal Pulse Status menu is displayed.
g. At the Internal Pulse Status menu, press
Edit Width and set pulse width W1 to 5.0 ms.
h.
Press Edit Period and set the PRI to 0.01 ms.
i.
Press On/Off to turn pulse modulation on.
2. Set the Oscilloscope controls as follows:
a. Vertical Sensitivity: 5 mV/div
b. External Trigger: On the positive slope of the
Channel 1 signal input
c. Horiz Time Base: 1 ms/div
NOTE
Use the Oscilloscope’s 20 MHz bandwidth
limit to aid in viewing the voltage spikes. It
may be necessary to adjust the Oscillo
-
scope’s horizontal level as any ripple or
voltage spikes are generally very small in
amplitude.
3. Measure and record the voltage spikes (video
feedthrough) on the Test Record. To meet specifi
-
cations, they must be <±10 mV.
3-44 682XXB/683XXB MM
PERFORMANCE PULSE MODULATION TEST:
VERIFICATION VIDEO FEEDTHROUGH