A customer asked me how fast the FFT appeared on the Tektronix MSO4104B. For thos who are unfamiliar with it, an FFT is a mathematical function that allows you to see the frequency content in a signal that is digitized in the time domain. By doing an FFT, you can use your oscilloscope like a spectrum analyzer. Most benchtop scopes have an FFT system, but on ones that do not run Windows, the FFT is often limited to only 1000 points. The problem is that with only 1000 points, your resolution bandwidth (or frequency visibility) is extremely limited.
The Tektronix MSO4104B can do very quick and lively FFT analysis up to 100k point records, and can actually crunch a 1M point record into an FFT as shown in the video below.
A Blog by Joel Avrunin on Electronics Test and Measurement, Focused on Oscilloscopes but covering a bit of everything!
