Specifications

148 Chapter 15
Concepts
Time Gating Concepts
Concepts
Figure 15-20 Gate Positioning Parameters
Most control settings are determined by two key parameters of the
signal under test: the pulse repetition interval (PRI) and the pulse
width (
τ). If you know these parameters, you can begin by picking some
standard settings. Table 15-2 and Table 15-3 summarize the
parameters for a signal whose trigger event occurs at the same time as
the beginning of the pulse (in other words, SD is 0). If your signal has a
non-zero delay, just add it to the recommended gate delay.
Table 15-2 Suggested Initial Settings for Known Pulse Width (τ) and Zero
Signal Delay
Pulse width (τ) Gate Delay
(SD +
τ/2)
Resolution
Bandwidth
(2>SUT)
Gate Length
(
τ/4)
Video Bandwidth
(1/gate length)
ESA gated video
only
4
µs3 µs1 MHz 1 µs1 MHz
10
µs5 µs1 MHz 3 µs1 MHz
50
µs 25 µs 100 kHz 13 µs
100 kHz
63.5
µs 32 µs 100 kHz 16 µs 100 kHz
100
µs 50 µs 100 kHz 25 µs 100 kHz
500
µs 250 µs 10 kHz 125 µs 10 kHz
1 ms 500
µs 10 kHz 250 µs 10 kHz
5 ms 2.5 ms 1 kHz 1.25 ms 1 kHz
10 ms 5 ms 1 kHz 2.5 ms 1 kHz
16.6 ms 8.3 ms 1 kHz 4 ms 1 kHz
33 ms 16.5 ms 1 kHz 8 ms 1 kHz
50 ms 25 ms 1 kHz 13 ms 1 kHz
100 ms 50 ms 1 kHz 25 ms 1 kHz
≥130 ms 65 ms 1 kHz 33 ms 1 kHz