Specifications

Chapter 8 65
Making Time-Gated Measurements
Gated Video Measurement (ESA)
Making Time-Gated Measurements
Step 3. Set the gate delay to 2 ms and the gate length to 1 ms. Check that the
gate control is set to edge with a positive trigger:
Press
Sweep, Gate, Gate Control (Edge).
Press
Edge Gate, Slope (Pos).
Press
Gate Delay, 2, ms.
Press
Gate Length, 1, ms.
Step 4. Turn the gate on:
Press
Sweep, Gate, Gate (On).
Figure 8-6 Viewing the FM Signal of a Pulsed RF Signal using Gated Video
Step 5. Notice that the gated spectrum is much cleaner than the ungated
spectrum (as seen in Figure 8-5). The spectrum you see is the same as a
frequency modulated signal without being pulsed. To prove this, turn
off the pulse modulation on ESG #1 by pressing
Pulse, Pulse so that Off
is selected. The displayed spectrum does not change.
Step 6. Check the oscilloscope display and ensure that the gate is positioned
under the pulse. The gate should be set so that it is on somewhere
between 25% to 80% of the pulse. If necessary, adjust gate length and
gate delay. Figure 8-7 shows the oscilloscope display when the gate is
positioned correctly (the bottom trace).
Figure 8-7 The Oscilloscope Display