72 Keysight N9923-90001 User’s GuideTime Domain – Option 010GatingGatingPerhaps the most beneficial feature of Time Domain transform is the Gatingfunction. When viewing the Time Domain response of a device, the gatingfunction can be used to “virtually” remove undesired responses. You can thensimultaneously view a frequency domain trace as if the undesired response didnot exist. This allows you to characterize devices without the effects of externaldevices such as connectors or adapters.Gating is best performed while viewing a Time Domain trace. Then, eitherdisable Transform, or separately view a frequency domain trace to see thetrace 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 notreach subsequent discontinuities. This can “MASK”, or hide, the trueresponse which would have occurred if the previous discontinuity were notpresent. The Gating feature does NOT compensate for this.
