Using Time-Gating To View Signal - HP 8590 E-Series User Manual

7. Set the video bandwidth to a value that is greater than 1 divided by the gate length. For
this example, the video bandwidth must be greater than l/13 ~LS, or 80 kHz. Press Isw),
VID BW AUTO MAN, 100 (kHz.
The spectrum analyzer displays only signal 1, not Both signal 1 and signal 2 (see
Figure 4-25).
CENTER 50.i00 "Ii;
Figure 4-25. Using Time-Gating to View Signal 1
8. To compare signal 1 to signal 2, we first place signal 1 (trace A) in the view mode. Press
9. To view the second signal, change the gate delay so that the gate output is under the
second signal. Since the second signal had a signal delay of approximately 85 ,q we set
the gate delay to 85 ,M plus the pulse width/2, or 110 p.s. Press CSWEEP], Gate Control ,
GATE DELAY 110 @ to set the gate delay to 110 ps. Using an oscilloscope can be helpful
in placing the gate output during the pulsed signal (see Figure 4-26).
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GATE DELAY
25 psec
GATE
LENGTH
EDGE POL