Use Matlab in a scope's data stream
Martin Rowe, Senior Technical Editor -- Test & Measurement World, 3/1/2006
Many oscilloscopes contain embedded PCs that run Windows, enabling you to install PC software, including programs that can perform data analysis right in the scope. To use such programs, you can operate the scope manually, store data in a file, and analyze your measurements. But you won't get the benefits of automation that way.
You can also "connect" data-analysis programs to a scope through the scope's instrument drivers. That lets you automate the signal acquisition, but you're just operating the scope as though it's connected to a separate PC. Thus, you're still analyzing data offline. You can, though, get real-time signal processing with Matlab.
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| Matlab can apply a digital filter to a waveform in real time. Courtesy of LeCroy. |
Matlab contains an ActiveX server that opens a communications path between the math software and a scope application. You can use the server to perform instrument control through drivers, but you can also use it to embed Matlab into a scope's data stream. By doing this, you can move data into Matlab, apply a signal-processing algorithm, and display the results as part of the scope's normal waveform display. With Matlab in the scope's data stream, you can filter signals (
figure), calculate the decay time in a damped sinusoid, extract a signal's fundamental frequency and convert the resultant signal back to the time domain, and automatically reposition an eye diagram to center it in a compliance mask.
