Approximating Periodic Signals with Finite Fourier Series

In this project, a matlab function will be used to show how a finite number of Fourier Series coefficients can approximate a periodic signal.

When there are only 1 non-zero term, the time and frequency domain are shown below:

When 2 non-zero terms


When 5 non-zeros terms


When there are 25 non-zero terms


Conclusion: From the above diagrams we are able to distinguish that: As the number of Fourier Series Coefficients increases, the output of approximated periodic signal is more accurate.


A circuit is built to measure the Fourier series of a Square wave


For example, we set s(t) to be square wave with A = 3V, T0 = 0.5*10^-6s


The frequency domain of output shown in spectrum analyzer will be:


The time domain of output shown in oscilloscope will be:




Back to 2018 Spring ECE 301 Boutin

Alumni Liaison

Correspondence Chess Grandmaster and Purdue Alumni

Prof. Dan Fleetwood