Using Signal Studio Software

Signal Studio applications provide software to generate statistically correct waveforms as defined by their respective standards. Each Signal Studio technology requires a license to enable connectivity to the PXB and a license for the associated software option or options. Several convenience bundles are available that enable MIMO channel configurations; others provide complete LTE or WiMAX™ software and channel model capabilities.

Refer to the Configuration Assistant to view all hardware, firmware, and software requirements for a particular configuration or technology that you want to use. The Licensing topic provides information on obtaining and installing a license in the PXB.

To run the Signal Studio software on the PXB

Although several Signal Studio applications are preloaded on the PXB when it is shipped, you can install or update Signal Studio software on the PXB or on a remote PC at any time. To ensure that you have the latest version of the software:  

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To create waveforms using Signal Studio applications

  1. In the PXB, select and load the predefined configuration that you want to use. Ensure that the PXB number of channels matches the number of antennas or output signals desired from the Signal Studio Application. If they are not the same, the Signal Studio Application will generate an error when downloading waveforms to the PXB.

  2. Start the Signal Studio software on the PXB or from a remote PC.

  3. In the Signal Studio software, select the ClosedRun System Configuration Wizard in the Signal Studio software tool bar to select the PXB hardware that you want to use. Waveforms will be automatically downloaded to the PXB according to this configuration and saved in the appropriate D:\Waveforms\ChannelN predefined directories. (ChannelN corresponds to the antenna or channel number; for example, Antenna 1 is saved to D:\Waveforms\Channel1.)

    Using the System Configuration Wizard in Signal Studio Applications

    The steps shown below are the same for all Signal Studio applications; however, the menu choices may differ depending on the application used. The illustrations displayed below use the N7624B Signal Studio for 3GPP LTE software.

    1. Select the number of antennas (I/O outputs) for your configuration.

    1. Select a hardware configuration.

     

    1. The remaining steps will vary depending on whether you are setting up a new hardware connection or using a previously configured hardware setup.

  4. Create the waveforms that you want to use. Refer to the Signal Studio application help system if you need information on its usage or functionality.

  5. Click Generate and Download in the Signal Studio software. The firmware verifies that a valid license for the waveform technology is installed on the PXB before generating and downloading the waveforms to baseband memory. An error message is displayed if there is a conflict between the configuration as set up in the software and the currently loaded configuration on the PXB.

Power Considerations

  • For MIMO configurations, the average power of the signal transmitted by one antenna is different than the average power transmitted by other antennas. When using Signal Studio applications that support connection to a PXB, the software provides Relative Amplitude cell settings that represent the power in the corresponding baseband generator (BBG) on the PXB relative to the power in the other BBGs. Refer to the help system for the software for more information on setting these parameters.

During download, the PXB runtime scaling is automatically adjusted to keep this relative amplitude on the output signal. Each of the external signal generators should be set to the power of the highest signal in the group.

  • For non-MIMO configurations, the runtime scaling is read from the signal studio waveform file, converted to dB, and read into the BB Gen runtime scaling property in the BB Gen settings on the PXB. It may be adjusted there or in the I/O output settings, or by changing the power on each signal generator.

  • When using a Signal Studio waveform (.wfm), the power control source will change automatically to "Waveform Header" and remain as the source until it is changed manually or the waveform type is changed to (.bin).

Marker Considerations

  • The PXB uses Makers 1, 3, and 4 for all maker event settings. (Maker 2 is reserved for internal use. If you assign Marker 2 in the Signal Studio application, it will be ignored by the PXB.)  

  • When there are multiple inputs feeding into a single output in a configuration, the Master Channel selected in the Output Marker tab determines the marker data for the output. However, individual markers may also be dynamically generated in the I/O output settings.

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To play the waveforms on the PXB

  1. Click Download Panel in the PXB tool bar. The Waveform Table that appears displays the associated file path, waveform name, and download status of the waveform for each baseband generator in your configured setup.

  2. If the download status displays "Up-to-Date" and the waveforms are correctly assigned, proceed to step 7. If you need to make changes to any of the waveforms that are currently downloaded, or assign a new waveform source file name to a baseband generator, proceed to steps 3 through 7 below.

To update a waveform before playing

  1. Generate and download the updated waveform from the Signal Studio software. You can also replace an existing file with one from the PXB hard drive or from a network drive by selecting a new waveform file in the Waveform Source Name cell in the respective BB Gen General Settings pane.

  2. Click Download Panel and notice that the Waveform Table now shows an "Out-of-Date" status for any waveforms that have changed.

  3. In the Waveform table, enable (check) the baseband generators to be reloaded with new or updated waveforms. Clear any that you do not wish to reload or that already display "Up-to-Date".

  4. Click Start to begin the download process. After a waveform file has been completely downloaded, the Waveform Status displays "Up-to-Date" and the Download Status column displays "Completed". Download times vary depending on the size and complexity of the waveforms being downloaded.

Waveforms must be downloaded to baseband memory after recalling settings, or executing a preset, or a power cycle. Waveform data is not saved as part of the PXB settings file; only file path information is saved.

 

  1. Click Play in the tool bar to play the waveforms on the enabled channels. Play is enabled once you have completely downloaded your waveform files to each BB Gen block in the PXB.
     

To ensure accurate power calibration during play, set the desired amplitude on either the signal generator or in the PXB Signal Generator General Settings pane. (Setting parameters in the signal generator requires an Update From Instrument to reset the user interface.)

The RF Output must be set to On in order for the signal to be visible out of the signal generator.

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