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

Basic Digital Operation (Option 651/652/654)I/Q ModulationI/Q ModulationThe following factors contribute to the error vector magnitude:• Differences in amplitude, phase, and delay between the I and Q channels• DC offsetsThe I/Q menu not only enables you to select the I/Q signal source and output, it also providesadjustments and calibrations to compensate for differences in the I and Q signals.See also, “Modulating the Carrier Signal” on page 61.Figure 8-15 I/Q Display and SoftkeysThis panel displays the currentsettings for the I/Q signal routingand I/Q correction optimized path.This panel displays the current status and settingsof the I/Q adjustments. Use the Page Up andPage Down keys to scroll through theseparameters. Grey indicates an inactive (off)adjustment.page 201These selections arereflected in theI/Q Routing &Optimization graphic.Inverts an internally generated Q signal, so that the I component lags theQ component by 90 degrees.Used only with internally generated, bursted modulationformats. Enables/disables the RF burst modulator.Opens the internal I/Q Equalization Filter which can be usedto correct and/or impair the RF and External I/Q outputs forthe internal I/Q source.Selects between optimizing the internal I/Q channel for EVM (in channelperformance) at the expense of ACP (out of channel performance) oroptimizing for ACP at the expense of EVM.EVM is an 80% nyquist filter (100Mhz wide) with a wide transition band.When an equalization filter is active, this filter is not active.ACP is also an 80% nyquist filter (100Mhz wide), but the transition bandis very narrow, thus reducing images for wide-band signals. This filter willbe convolved with the active equalization filter, the result of which will betruncated to the center 256 taps.SCPI Commands:[:SOURce]:DM:INTernal:CHANnel:OPTimization EVM|ACP[:SOURce]:DM:INTernal:CHANnel:OPTimization?Each path requires different optimization values;when you select a path, you are selecting theunique optimization values required by that path.The signal generator applies the selectedoptimization values to both paths, which impairsthe unselected path.For details on each key, use key helpas described on page 42.198 Agilent N5161A/62A/81A/82A/83A MXG Signal Generators User’s Guide