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

Basic Digital Operation (Option 651/652/654)Understanding Option 012 (LO In/Out for Phase Coherency) with Multiple Baseband Generator Synchronization2x2 MIMO (LO In/Out for Phase Coherency) ConfigurationFor the 2x2 MIMO (LO In/Out for phase coherency) setup, the LO from the master MXG can be ranthrough a power splitter and used as the LO input to both the master and the slave MXGs. Noexternal source is required.To generate phase coherent signals for a 2x2 MIMO configuration, the master MXG LO OUT isconnected via a power splitter to the slave LO IN. The LO OUT provides a sufficient amplitude LOsignal when connected directly, to drive the Slave MXG(s), thus providing phase coherency for the RFoutput signals. In this example, we show two MXG signal generators with Option 012 connected for aphase coherent 2x2 MIMO solution. Refer to Figure 8- 30.Figure 8-30 2x2 MIMO (LO In/Out for Phase Coherency) Equipment SetupNote:To optimize the phase coherence, the same length SMA flexible cable is recommended for the output of the 2–way splitterconnections to the LO IN of the MXGs with Option 012 (see page 225).To minimize synchronization delay, the Agilent BNC cable 10502A is the recommended cable for the rear panel daisy chain3x3 and 4x4 MIMO (LO In/Out for Phase Coherency) ConfigurationsFor a 3x3 and 4x4 MIMO (LO In/Out for phase coherency) setups, an additional analog source isneeded to provide the higher LO power required by the power splitter and the additionalinstruments.Splitting the LO output four ways causes too much loss to drive the LO input of the N5162/82As inthe system. Also, there is no amplitude adjustment to the LO output of the N5162A/82A. To generatephase coherent signals for a 3x3 and 4x4 configurations with the MXG, an external Master LO isneeded to provide a sufficient amplitude LO input signal to the vector MXGs (refer to Figure 8- 31 onpage 228).NOTEThe Master LO is not controlled by any of the Signal Studio software, but must be setmanually—via the RF frequency settings on the master MXG—by the user to the desiredfrequency and amplitude.Agilent N5161A/62A/81A/82A/83A MXG Signal Generators User’s Guide 227