[fpc-pascal] Good FFT example anywhere?

Bo Berglund bo.berglund at gmail.com
Sun Apr 9 20:24:21 CEST 2017

On Sun, 9 Apr 2017 08:01:07 -0700 (MST), fredvs
<fiens at hotmail.com> wrote:

>> I was using attached unit some 7 years ago for various speech processing
>> purposes.
>+ @Martin
>Can those units be used for sound samples (array of float32 or array ot
>integer 32/16) ?

The unit declares the fft procedure like this:

procedure fft

Calculates the Fast Fourier Transform of the array of complex numbers
represented by 'RealIn' and 'ImagIn' to produce the output complex
numbers in 'RealOut' and 'ImagOut'.
procedure fft (
    NumSamples:   word;   { must be a positive integer power of 2 }
    var  RealIn:   array of double;
    var  ImagIn:   array of double;
    var  RealOut:  array of double;
    var  ImagOut:  array of double );

As you can see it uses double, which means you will be OK to supply
both single and integer values, just load the array with them and they
will be converted.

Bo Berglund
Developer in Sweden

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