Re: Altivec FFT
Re: Altivec FFT
- Subject: Re: Altivec FFT
- From: Kurt Bigler <email@hidden>
- Date: Tue, 27 Jan 2004 20:52:09 -0800
on 1/25/04 7:34 PM, Daniel Todd Currie <email@hidden> wrote:
>
I'm no expert, but isn't FFT for decomposition of acquired data?
FFT is equally useful for either for analysis or synthesis.
Generating a sine wave is a reasonable test case - just put a 1 in any slot
and 0's in all the others and you will get your sine. For square wave you
have to know the harmonic structure involving odd harmonics with certain
coefficients.
Sorry just general information - I'm not familiar with vDSP yet.
-Kurt
>
>
If I wanted to create a buffer of sinewave data, I would think it far
>
easier to just do:
>
>
unsigned i;
>
float sineBuffer[512];
>
float desiredFrequency = 440; // 440 Hz, for example
>
>
while(i < 512)
>
{
>
sineBuffer[i] = sin(2 * M_PI * i * (desiredFrequency / 44100)); // for
>
sample rates of 44.1 kHz
>
}
>
>
// Daniel Currie
>
>
>
On 2004 Jan 25, at 18:24, John Mullins wrote:
>
>
> Hey,
>
> I'm trying to use the FFT functions in vDSP to generate Sine, Square,
>
> etc, but I'm pretty clueless as to how to accomplish this. If someone
>
> could send me the code to generate a sine wave with it, or some
>
> already existing sample code that would be great.
>
>
>
> I don't really understand how to actually grab from the table , or
>
> where it puts the information generated... thanks
>
>
>
> John Mullins
>
> email@hidden
>
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