Keysight EXG and MXG X-Series Signal Generators User’s Guide 121Optimizing Performance for All ModelsUsing Unleveled Operating ModesUsing Unleveled Operating ModesFigure 5-23 Power Search and ALC Off SoftkeysALC Off ModeTurning ALC off deactivates the signal generator’s automatic leveling circuitry. Turning ALC off isuseful when the modulation consists of very narrow pulses that are below the pulse widthspecification of the ALC or when up converting external IQ signals and the modulation consists ofAvailable only whenALC = OffAvailable only whenPower Search Reference =Available only whenPower Search = SpanAuto: The calibration routine executes wheneveroutput frequency or amplitude changes.Span: Pressing Do Power Search executes thepower search calibration routine once over aselected frequency range.The corrections are stored and used whenever youtune the signal generator to within the calibratedfrequency range.For details on each key, use key help as described on page 56.RMS: Value is a DCbias equivalent to thevalue derived from thefile header or thecalculated value fromthe current I/Q data.Fixed: Uses a fixed 0.5Vrms value (Samevalue is used with ExtI/Q data).Manual: Allows user tospecify the DC biasvoltage value(0–1.414 Vrms).Modulated: Uses theAC bias from the actualmodulating signal.ManualUser: Enables theuser to set thesignal generatorfrequency settings.Full: The signalgenerator selectsits full frequencyrange for the powersearch.Only available whenI/Q is on.Thesesoftkeys areonly activewhen an ARBwaveforms isplaying inmemory. Manual: User must explicitly execute a powersearch to calibrate the open loop ALC level.See page 101Sets the allowedsettling error.Only available whenI/Q is on.N5173B/83B onlyN5173B/83B only
