# 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: 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.

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

1. GOITY says:

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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