FFT and Spectra

In this lab, students will investigate the frequency spectrum of common signals by using the FFT mode of the Oscilloscope and relate this to the signals in the time domain. By understanding the frequency domain characteristics of various signal types, we can further develop our ability to think in both the time AND frequency domain when considering signals. The two go hand in hand and it is essential for the engineer to be well versed in both.
by Emona Tims

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This is lab 3 of 20 in the course, Communications Principles.


After completing this lab, students will be able to:
  1. Understand the spectrum of an impulse train.
  2. Understand the spectrum of a filtered impulse train.
  3. Understand the relationship between the duty cycle of a periodic pulse train and its spectrum.
  4. Understand the finite spectrum of a sinc pulse train.
  5. Understand the spectrum of variable-length pseudorandom sequence and how such sequences can be used for analog noise generation.
  6. Understand the effects of clipping and half-wave rectification on a signal’s spectrum.


  • Basic proficiency using ELVIS III Instruments
  • Basic Circuits Knowledge


Engineering laboratory solution for project-based learning that combines instrumentation and embedded design with a web-driven experience, delivering a greater understanding of engineering fundamentals and system design.

Emona Communications Board for NI ELVIS III

Application board for the NI ELVIS III developed to teach introductory digital and analog communications topics using a completely hands-on approach.


Instructor resources are available. Get access

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