Keysight N9923A, User Manual, Page: 72 / 276

72 Keysight N9923-90001 User’s Guide
Time Domain – Option 010
Gating
Gating
Perhaps the most beneficial feature of Time Domain transform is the Gating
function. When viewing the Time Domain response of a device, the gating
function can be used to “virtually” remove undesired responses. You can then
simultaneously view a frequency domain trace as if the undesired response did
not exist. This allows you to characterize devices without the effects of external
devices such as connectors or adapters.
Gating is best performed while viewing a Time Domain trace. Then, either
disable Transform, or separately view a frequency domain trace to see the
trace with the gated effects removed.
The following image shows how gating can affect measurement results.
All 4 traces show the same S11 measurement.
Trace 1 shows the
frequency
response
without
gating enabled.
Trace 2 shows the
transform
response
without
gating enabled.
Trace 3 shows the
transform
response
with
gating enabled.
When a discontinuity in a test device reflects energy, that energy will not
reach subsequent discontinuities. This can “MASK”, or hide, the true
response which would have occurred if the previous discontinuity were not
present. The Gating feature does NOT compensate for this.