[PD] Normaliizing sinus mix

João Pais jmmmpais at gmail.com
Mon Apr 30 17:10:29 CEST 2018


>> I'm not sure: if I use the amplitudes 1 0.5 0.25, the peak amplitude is
>> 1, and the wave is clearly outside of the 1/-1 boundaries.
>
> then you are doing something wrong.
> why do you think the maximum of abs(sin(t)+½sin(2t)+¼sin(4t)) is "1"?
>
> to analytically get the maxima of this function, you probably have to
> recall your high-school maths (get the derivative of the function
> (without the abs()), set it to "0" and solve it for every t to find the
> positions of the extrema; use these t's to get the values of the extrema)

since I almost flunked at math in high school, that's probably why I  
didn't know what the peak amplitude was.

One thing about that context that I didn't explain: I'm not using an array  
to read the waveshape, but adding the individual waves separately, so that  
I can change the amplitudes dinamically each time the phase of each  
partial is 0 (if I do it with sinesum+normalize, there's always clicks). I  
was hoping to apply the formula of normalize directly, but now it seems  
that the easiest way is to use sinesum+normalize in parallel as a fast way  
to get the peak amplitude.

Best,

Joao

>> Basically what I'm trying to do is to find out what is the formula that
>> does the "normalize" function.
>
> however, the "formula" of "normalize is very simple:
> - take a table
> - iterate over all the elements of the table and get the maximum value
> (absolute) you find in there
> - iterate over all the elements of the table and divide each element by
> the just found maximum.
>
> gfmasdr
> IOhannes
>
>


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