Making Measurements Using Spectrum Analyzer Mode

Using the Time-Gated Spectrum Analyzer Capability Without the Gate Utility (Option 107 only)

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 ps, or 80 kHz. Press m, YID BW AUTO MAN , 100 (iZJ

See Figure 5-23. The spectrum analyzer displays only signal 1, not both signal 1 and signal 2.

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Figure 5.23. 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 (ml, VIEW A , TRACE A B C (so that B is underlined), CLEAR WRITE B

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 ps, we set the gate delay to 85 ps plus the pulse width/2, or 110 ps. Press [SWEEP], 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 5-24.

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