ACF of a rectangle

[Christian Kaernbach <mailinglist@xxxxxxxxxxxx>]

Eckard Blumschein wrote:
> The spectrum of the pure tone is a single frequency. Its ACF resembles a
> comb. It sounds harmonical.
>
> The spectrum of the rectangle is comb-like. Its ACF is a single
> autocorrelation lag. It sounds sharp.
The energy spectrum of a periodic rectangle waveform is "comb-like" with
peaks decreasing as 1/n^2 (odd peaks only). The second peak is 1/9 of
the first. A short comb, indeed...

The ACF of a periodic rectangle waveform is a periodic triangluar waveform.

Best,
Christian Kaernbach