Fast fourier transforms with an oscilloscope

Posted By : Lanna Cooper

What is fast fourier transform and why do I care about it? If there is unwanted frequency content in your design, it could interfere with other components, cause excess noise, or even voltage spikes that can cause your device to malfunction. 

If you don’t analyse the frequency components of your signal, you will never know that unwanted content is there. You can easily do this on an oscilloscope using Fast Fourier Transform, or 'FFT'.

Typically, people don’t associate an oscilloscope with frequency analysis, but it is the perfect tool for analysing the frequency content of your digital signals. An FFT is just a math operation on the oscilloscope. This math operation basically splits apart the signal that you see in the time domain, then translates that into the frequency domain. This is shown on a graph in amplitude vs. frequency.

Often times, there are problems that you can’t even see in the time domain, so having the ability to view the frequency domain can reveal errors and glitches in your device you didn’t even know were there. Having this capability on an oscilloscope just makes this analysis even more convenient.

You will learn how to set up an FFT on an oscilloscope in order to verify your design and understand what it is that is causing any errors.

Scopes University is hosted by Erin East and Melissa Spencer. The video series covers when and how to use different applications and capabilities of the InfiniiVision and Infiniium oscilloscopes. You’ll gain familiarity with features that will help you save time in your measurement, further your analysis, and deepen your insight.

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