How Time Gating Works - Keysight X Series Measurement Manual

How time gating works

Time gating is achieved by the signal analyzer selectively interrupting the path of the
detected signal, with a gate, as shown in
determines the times at which it captures measurement data (when the gate is turned
"on," under the Gate menu, the signal is being passed, otherwise when the gate is
"off," the signal is being blocked). Under the right conditions, the only signals that
the analyzer measures are those present at the input to the analyzer when the gate is
on. With the correct signal analyzer settings, all other signals are masked out.
There are typically two main types of gating conditions, edge and level:
• With edge gating, the gate timing is controlled by user parameters (gate delay and
• With level gating, the gate will pass a signal when the gate signal meets the
Figure 15-7 Edge Trigger Timing Relationships
With Keysight signal analyzers, there are three different implementations for time
gating: gated LO, gated video and gated FFT.
gate length) following the selected (rising or falling) edge of the trigger signal.
The gate passes a signal on the edge of the trigger signal (after the gate delay time
has been met) and blocks the signal at the end of the gate length.
With edge gating, the gate control signal is usually an external periodic TTL
signal that rises and falls in synchronization with the rise and fall of the pulsed
radio signal. The gate delay is the time the analyzer waits after the trigger event
Figure
to enable the gate (see
specified level (high or low). The gate blocks the signal when the level conditions
are no longer satisfied (level gating does not use gate length or gate delay
parameters).
Figure 15-9
15-7).
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Concepts
Time Gating Concepts
Figure 15-8
and The gate