topic Re: Need help with inverse FFT in Intel® Integrated Performance Primitives

Need help with inverse FFT

as1 — Sat, 26 Feb 2005 01:49:41 GMT

I'm in the process of converting from older signal processing liobraries (I think ISPL 4.5), and having some troubles with generating an audio sample with reverse FFT. With the old libraries to generate, let's say for simplicity, 1Khz toneI used to zero a buffer, fill it with a value at [ 1000 * FFTSize / SamplingRate * 2 ], and then ran nspdRealFft( Buffer, FFTOrder, NSP_Inv ). That did it, the sine wave was there. The new libraries changed a lot in the FFT department, so whatever I do don't seem to generate a sine wave but rather some bizzare distortedsignal. Can anybody help me with 1Khz tone and sequence of IPP functions I have to call?

Thanks, Anton

PS. I used 1Khz as an example, the signal I'm tring to generate is quite different (specially formed noise) and I really cannot use other signal generating techniquies.

Re: Need help with inverse FFT

as1 — Tue, 01 Mar 2005 02:06:18 GMT

Never mind, I fiigured it out. Scaling has changed and was wrong, so I was just overloading theoutput, hence distordedwaves.

Re: Need help with inverse FFT

Vladimir_Dudnik — Thu, 10 Mar 2005 22:41:23 GMT

Hi,

that's great that you were able to migrate from old libraries to IPP. BTW, what is your feeling about IPP, are you satisfied with functionality, performance, documentation, samples? Your feedback will help us to keep improving IPP in the next versions.

Regards,

Vladimir