Manual Synchronization of MIMO Systems

When Signal Studio is used to download and initiate waveform playback in multiple instruments, it sends SCPI commands to set up the triggering parameters and initiate the waveform playback so that the playback starts at the same time in each instrument. If you choose to store waveforms in the instruments and recall them for playback from the instrument memory, rather than using Signal Studio directly, additional steps are needed to get synchronized waveform playback. The front panel keystrokes in the procedure below can be replaced by SCPI commands in a software program.

First, connect the instruments as shown in the Tutorials section of the online help for your desired configuration:

E4438C ESG or E8267D PSG Instrument Setup

Make sure that the EVENT 2 output of the master ESG/PSG is connected to the PATT TRIG IN 1 connectors on both the master and slave ESGs/PSGs. The 10 MHz references should be connected between the instruments.

For each instrument, press these keys: Preset > Mode Setup > Dual Arb > Trigger > Trigger Setup > Trigger Source > Ext Source and verify that Patt Trig In 1 is selected. Next, press Return > Continuous Mode and set this to Trigger & Run. This will set up the instrument to start playing back the waveform continuously when it receives an external trigger input on the PATT TRIG IN 1 connector, and to ignore further trigger signals.
On each instrument, select the desired waveform, but leave the ARB turned off:
1. Press Mode > Dual ARB > Waveform Segments, select and load the desired segment(s).
2. Press Return > Select Waveform, and select the desired waveform file.
Send the following SCPI commands to the master ESG or PSG to prepare it to output periodic triggering pulses on the EVENT 2 output. If you are not using a software program to control the test, you can use the Keysight Connection Expert to connect to the instrument and send the following SCPI commands:

diag:bbg:mon "ww a6000004 30"

diag:bbg:mon "ww a6000058 6000"

diag:bbg:mon "ww a600005c 6001"
Turn on the ARB in each instrument: Local > Mode Setup > ARB On (if needed). Set the desired frequency and amplitude for the output signal and turn RF on. See Power Settings for N7615C Signal Studio for Mobile WiMAX for information about setting N7615C waveform power.
Send these SCPI commands to the master ESG or PSG to generate the trigger pulses to start the waveform playback and to stop the pulse generation. No delay is needed between the commands since the hardware works faster than the SCPI command processing.

diag:bbg:mon "ww a6000056 3"

diag:bbg:mon "ww a6000056 0"

Turning off the ARB on any of the instruments will cause a loss of synchronization. To re-synchronize the waveform playback or change to a different waveform(s), repeat steps 2-5.

MXG/EXG X-Series Signal Generator Setup

Make sure that the EVENT 1 output from the master MXG/EXG is connected to the PAT TRIG IN on the slave MXG/EXG. The 10 MHz references should be connected between the instruments.

You can use multiple N5182A signal generators in the same system, or you can use N5172B and N5182B signal generators in the same system. However, you cannot use a mixture of N5182A signal generators and N5172B or N5182B signal generators in the same system.

If you are using an N5172B or N5182B and one or more N5182A signal generators, you must configure the N5172B or N5182B as the Master. In addition, the N5182A slaves must be at the end of the instrument chain.

On the master MXG/EXG, press these keys to set up the trigger type, trigger mode, and trigger source: Preset > Mode > Dual ARB > Trigger Type > Continuous > Trigger & Run > Trigger Source > Trigger Source. Here you can choose Trigger Key, Bus, or Ext as the trigger source. Trigger Key is convenient for manual operation. Bus trigger can easily be sent with a SCPI command so that is a good choice if the measurement is automated. Ext uses an external trigger signal applied to Patt Trig In 1 (by default), which is the PAT TRIG rear panel connector.
If Ext was selected for the Trigger Source, disconnect the external trigger signal from the PAT TRIG input on the master MXG/EXG.
On the slave MXG/EXG(s), press these keys to set up the trigger type and trigger mode. The default trigger source of Patt Trig will be used: Preset > Mode > Dual ARB > Trigger Type > Continuous > Trigger & Run. Press these keys to verify that the trigger source is set to External, with External defined to be the rear panel Patt Trig In 1 input: Trigger Source > Trigger Source > Ext > Ext Source > Patt Trig In 1 > Ext Polarity Pos.
Press these keys to set up the master MXG/EXG for the Multi-BBG Sync function: Mode > Dual ARB > ARB Setup > More > Multi-BBG Sync Setup > Multi-BBG Sync Type > Master then
- for a N5182A master, set Number of Slaves as appropriate.
- for an N5172B or N5182B master, set Total Number of Slaves and Number of MXG-A Slaves as appropriate.
On each slave MXG/EXG, press these keys to set up the Multi-BBG Sync function: Mode > Dual ARB > ARB Setup > More > Multi-BBG Sync Setup > Multi-BBG Sync Type > Slave then
- for a N5182A slave, set Number of Slaves and Slave Position as appropriate.
- for an N5172B or N5182B slave, set Total Number of Slaves, Number of MXG-A Slaves, and Slave Position as appropriate.
On each slave MXG/EXG, press Listen for Sync.
On the master, press Sync Slaves. The status on all MXG/EXGs should show In Sync.
In each MXG/EXG, select the desired waveform file and turn Arbs ON: Mode > Dual ARB > Select Waveform > Waveform Segments to load the waveform files into the baseband generator memory if needed, then highlight the desired waveform file and press Select Waveform > ARB On. Set the desired frequency and amplitude for the output signal and turn RF on. See Power Settings for N7615C Signal Studio for Mobile WiMAX for information about setting N7615C waveform power
Initiate the waveform playback using one of these steps, depending on which Trigger Source was selected in step 1:
1. Trigger Source = Trigger Key: press Trigger to start the waveform playback.
2. Trigger Source = Bus: Send the *TRG SCPI command to the master MXG/EXG. If you are not using a software program to control the test, you can use the Keysight Connection Expert to connect to the instrument and send the SCPI commands.
3. Trigger Source = Ext: Connect the external trigger signal to the PAT TRIG input on the master MXG/EXG.
To change waveforms or resynchronize the MXG/EXGs:
1. If using an external trigger for the master MXG/EXG, disconnect it or turn it off.
2. Turn off all of the ARBs by pressing Mode > Dual ARB > ARB Off and press ARB Setup > More > Multi-BBG Sync Setup on each MXG/EXG.
3. Repeat steps 6 through 9.

Power Settings for N7615C Signal Studio for Mobile WiMAX

When two instruments are directly controlled by the N7615C Signal Studio software, you set the desired amplitude for the master instrument, but Signal Studio will automatically set the amplitude on the slave instrument to get the correct output power for the Antenna 1 signal (see Power Settings for more information). When Signal Studio is not used to directly download the waveforms and control the Instruments, you are responsible for selecting the correct amplitude setting for the slave instrument. Keysight recommends that you make a note of the relative power settings for the master and slave instruments when you first create and download each set of waveform files. The amplitude settings can be found by clicking on Instrument in the Closed tree view after the waveform files have been generated. You can also save the instrument state in the instruments for later use by creating a Quick Setup.