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

Basic Digital Operation (Option 651/652/654)Multiple Baseband Generator SynchronizationCommon uses for the real- time modulation feature include:• Where the single carrier rectangular ideal I/Q symbol decision points are known and are to havean over- sampled filter applied.• Where greater effective MXG memory size is required.• When you have a low rate waveform that could benefit from a higher OSR that does not make thewaveform longer.The real- time modulation filter setup is one of the file header parameters (page 149), which meansyou can store this setup with the waveform. When you select a waveform with a stored modulationfilter setup, the signal generator changes the current setup to match the stored file header setup. Ifthere is no stored modulation filter setup for the current waveform, the signal generator uses the lastset modulation filter setup.You can also use the Save function (page 71) to store this value as part of the signal generator setup.When you Recall a setup stored with the Save function, the modulation filter value becomes thecurrent instrument setting value, disregarding the stored file header value.Use the following steps to apply a real- time modulation filter to the current waveform loaded intovolatile memory. This example uses the factory supplied waveform, SINE_TEST_WFM available in theDual ARB Player. To view the output for this example, connect the RF OUTPUT of the signalgenerator to the input of a spectrum analyzer.NOTEThe following setup assumes you have completed the setup in “Setting the BasebandFrequency Offset” on page 194 for creating a modulated RF signal that is offset from thecarrier frequency by 20 MHz.1. Configure the modulation filter:Press Mode > Dual ARB > Arb setup > More > Real-Time Modulation Filter > Select > Root Nyquist2. Press Filter Alpha > .4 > Enter.The modulated RF signal now has a real- time modulation filter of type root nyquist, with a filteralpha of 0.400.Multiple Baseband Generator SynchronizationAvailable in the Dual ARB menu, this feature lets you set up a master/slave system of up to sixteenAgilent MXGs so that the baseband generators (BBG) synchronize the playing of waveforms. Thesystem count includes one Agilent MXG to function as the master (see “Equipment Setup” onpage 222).The MXG with Option 012, enables 2x2, 3x3, or 4x4 MIMO configurations to share a common externalLO signal to create phase coherent system. Refer to “Understanding Option 012 (LO In/Out for PhaseCoherency) with Multiple Baseband Generator Synchronization” on page 225 and the Data Sheet.218 Agilent N5161A/62A/81A/82A/83A MXG Signal Generators User’s Guide