Baseband Generator Setup

As noted in the Configuration Basics tour, a fully configured and licensed PXB has12 independent DSP blocks that can do either baseband generation or fading. If you choose a predefined configuration that includes a baseband generator, you are telling the PXB that you want to configure one of your DSP blocks to act as a baseband generator. Just remember that each baseband generator or fader consumes a DSP block.

Before you can set up a waveform and baseband generator, you first need to (1) assign your external instruments and (2) load your chosen configuration as shown in the External Instruments tutorial video.

Once your configuration is loaded, you'll need to set up your waveforms and baseband generators. Your waveform options depend on whether you are using real time generation or arbitrary (ARB) waveform generation. If you selected a Signal Studio real time generation format when you loaded your configuration, the block diagram will display a waveform block named after the real time signal format followed by a BBG block. If you selected ARB waveform generation, you will see a waveform block called "User File" followed by a BBG block. Either way, you will want to first set up the waveform block then the BBG block.

First, click the waveform block (w) or the corresponding node in the Settings Browser (User File node for ARB waveforms, <format name> node for real time). This is where you'll find waveform-specific settings, like waveform source file location for ARB waveforms and signal and payload settings for real time.

• For ARB waveform generation, you must at least set the path for the waveform source file to be played. You could set a different source file for each baseband generator, or you could choose the same file for each, depending on your testing needs. See the online documentation's ARB Waveform section for descriptions of ARB waveform settings.

• For real time generation, the available settings depend on the Signal Studio real time format you are configured to use. See the online documentation's Signal Studio Real Time Generation section for descriptions of ARB waveform settings.

Next, configure the baseband generator settings by either clicking a BBG block or by selecting a BBG node in the Settings Browser.

Within each baseband generator, you can control general settings, marker generation settings and power calibration settings for the selected baseband generator. This tutorial will just look at the general settings panel. 

• The General Settings panel gives you control of settings that are specific to this baseband generator. For example, you can enable or disable a baseband generator during waveform playback to temporarily set the output of the block to all zero data. See the online documentation's Baseband Generator topic for descriptions of all of the baseband generator settings.  

• When you’re finished setting up your baseband generators, load your waveforms into the PXB’s working memory using the Download Panel. This displays a waveform table showing the status of the waveforms used in your configuration. An "Out-of-Date” status means that the waveform file has never been loaded or has changed since the last time it was loaded. Check the files you want to load and click Start. When your waveforms are finished loading, their status should be "Up-to-Date.”  

Returning to the Block Diagram view, note the "On” buttons on all of the functional blocks. These buttons control each block’s Enabled setting so you can use the Block Diagram view as a control panel and easily manipulate your signal while it is playing.