Friday Math Movie – Sine Wave to Square Wave using Fourier Series

By Murray Bourne, 14 Nov 2008

We learned about sine waves in elementary trigonometry:

Graph of a sine curve

The idea behind the Fourier Series is to add sine curves with different amplitudes and frequencies and the resulting curve can be either a square wave, a sawtooth wave or many other interesting periodic shapes. You can see more on this concept in this Introduction to Fourier Series.

This week’s movie begins with a pure sine wave tone and then the other sine curves are added to it to produce something very close to a square wave (with the odd wiggle here and there) as the number of added curves becomes very large.

Warning: The final square wave tone may be pretty loud.

See the 3 Comments below.

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3 Comments on “Friday Math Movie – Sine Wave to Square Wave using Fourier Series”

  1. GOITY says:

    Your work is very awsome..^^ please show us your solution in solving higher dimension^^

  2. gagangc says:

    Sir.
    building a square wave from sine wave is easy as square wave is periodic.how to claculate fourier series of
    y=x? it dont have period as it doesnt repeat itself.

  3. Murray says:

    @gagangc: The original function has to be periodic – otherwise you can’t form a Fourier Series!

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