4-14. PULSE MODULATION VIDEO FEEDTHROUGH TEST (Cont’d)
3. Set both oscilloscope channels (A and B) to 50 Ohm input. Set the oscilloscope to view the pulse
generator output waveform. Adjust the HP 8012B pulse width VERNIER for a 100 nanosecond
pulse. Adjust the pulse period VERNIER for a 100 microsecond period. Adjust the amplitude
VERNIER for about a 3V pulse amplitude (TTL level). Set the oscilloscope horizontal sweep to 50
nanoseconds/division and select channel A input only.
4. On the DUT, press
[INSTRPRESET] followed
by [CW] [.] [4] [GHz].
Press the [PULSE]key (pulse
ON).
5. Press the
[POWERLEVEL]
key and enter the first power level
[8] [dBm].
6. Adjust the oscilloscope channel A vertical sensitivity and vertical position to view the video
feedthrough signal similar to Figure 4-18.
7. The test limits for the three power levels are shown in Table 4-28. (Note that the test limit is 5% of
Vpk.)
Table 4-28.
Pulse Modulation Video Feedthrough Test Limits
HP 8340B141B
RF Output
Level (dBm)
‘
‘dB’
1m,
Vpk
TEST
LIMIT
(pk voltage)
+8
0
—10
—2
—10
—20
0.2511
0.0999
0.03162
12 mV
5 mV
1.6 mV
Figure 4-18.
Pulse Modulation Video Feedthrough Waveform
HP 8340B/41B
Performance Tests
4-69
