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by tkok 5473 days ago
Audio signals are alternating. The voltage corresponds to the sound pressure picked up by the microphone, which typically looks more or less like a bunch of sinusoids.
1 comments
kwantam 5473 days ago
It's not just typically a bunch of sinusoids: Fourier tells us that it is always the sum of a bunch of sinusoids.

[1] http://en.wikipedia.org/wiki/Fourier_transform

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