DSO Use and Fundamentals

Question: I have a fairly new DSO and I need a good book on DSO use and fundamentals (I’m an analog power & interface guy) so I can get into the newer technologies, especially spectrum display and FFT functions. Most all of what I see on the net is older data and I’m not sure how it may relate to a new scope.   Can you recommend a good book, or other source of technical information?

Answer:  We have a great 64-page primer “XYZs of Oscilloscopes” which gives an overview of oscilloscopes and their major features and functions.  That’s probably a good starting point for learning about DSOs.  We also have an “Introduction to Oscilloscopes” lab that is used by university students to acquaint themselves with digital oscilloscopes.  You might take an hour and go through those exercises.  In the lab, we cover important topics like setting the horizontal and vertical systems, triggering, record length, measurements and more.

 FFT measurement algorithms vary from scope to scope.  The number of points used for the FFT, for instance, can differ, as well as the type of windows available.  As you might recall from FFT theory, windows allow you to tradeoff the frequency resolution and amplitude accuracy that you will see in your FFT spectrum.  Common window types include:

  • Rectangular: Best frequency resolution, worst amplitude accuracy. Used with non-periodic signals such as pulses and transients.
  • Hanning: Good frequency resolution, very good amplitude accuracy. Used for periodic signals.
  • Hamming: Very good frequency resolution, good amplitude accuracy. Used for periodic signals.
  • Blackman-Harris: Worst frequency resolution, best amplitude accuracy. Used with predominantly single-frequency waveforms to look for harmonics.

We have a good application note that goes through setting up a FFT on one of our TDS oscilloscopes.  This application note should give you some good pointers.

Explore posts in the same categories: Ask Scope Guru Q/A, Oscilloscope Fundamentals

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