N5161A/62A/81A/82A/83A MXG Signal Generators User's Guide

Basic Digital Operation (Option 651/652/654)Using Waveform MarkersALC Hold Marker FunctionWhile you can set a marker function (described as Marker Routing on the softkey label) either beforeor after you set marker points (page 162), setting a marker function before setting marker points maycause power spikes or loss of power at the RF output.Use the ALC hold function by itself when you have a waveform signal that incorporates idle periods,burst ramps, or when the increased dynamic range encountered with RF blanking (page 166) is notdesired.The ALC hold marker function holds the ALC circuitry at the average value of the sampled pointsset by the marker(s). For both positive and negative marker polarity, the ALC samples the RF outputsignal (the carrier plus any modulating signal) when the marker signal goes high:Positive:NegativeThe signal is sampled during the on marker points.The signal is sampled during the off marker points.NOTEBecause it can affect the waveform’s output amplitude, do not use the ALC hold for longerthan 100 ms. For longer time intervals, refer to “Power Search Mode” on page 113.Positive PolarityCAUTIONIncorrect ALC sampling can create a sudden unleveled condition that may create a spikein the RF output, potentially damaging a DUT or connected instrument. To prevent thiscondition, ensure that you set markers to let the ALC sample over an amplitude thataccounts for the higher power levels encountered within the signal.Agilent N5161A/62A/81A/82A/83A MXG Signal Generators User’s Guide 157