A simple-to-use sound file writer

Steve Holden steve at holdenweb.com
Thu Jan 14 17:07:07 CET 2010


Alf P. Steinbach wrote:
> * Steve Holden:
[...]
> With the goal of just a rough approximation you can go about it like this:
> 
>   1. Divide a full cycle of the sine wave into n intervals. With
>      sine wave frequency f this corresponds to n*f sample rate for digital
>      representation.
> 
>   2. Each interval will be approximated by a rectangular bar extending
>      up to or down to the sine wave. As it happens this (the bar's
> height) is
>      the sample value in a digital representation.
> 
>   3. In the first half of the cycle, for each bar create that bar as
>      a square wave of frequency f, amplitude half the bar's height, and
> phase
>      starting at the bar's left, plus same square wave with negative sign
>      (inverted amplitude) and phase starting at the bar's right. And voilà,
>      not only this bar generated  but also the corresponding other-way
> bar in
>      second half of cycle.
> 
>   4. Sum all the square waves from step 3.
> 
>   5. Let n go to infinity for utter perfectness! :-)
> 
> And likewise for any other waveform.
> 
> After all, it's the basis of digital representation of sound!
> 
> 
I'm sorry, but this is merely hand-waving. It looks appealing, but
there's no rigor there.

regards
 Steve
-- 
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