Hai to all, Iam new to this forum and dsp. Iam involved in converting a 5sec voice to frequency using a fft. Using pic24f series i need to accomplish this. Can anyone guide through this process? What should be my sampling rate, How can i convert the digital samples into real and imaginary parts, since the c coded fft requires real and imaginary parts as arguments to fft.How many point fft should i implement? Please help me through.
Thanks in advance, Siva
Sorry for my bad english, i am here in germany
First, You need a low-pass filter. Then your sample rate has to be faster than twice the maximum frequency which comes throug your filter.
For the calculation, you can simly take the imagimary values of the input signal as zero. With FFT, you then get a complex spectrum. From this, you can calculate the power-spectrum by x = const *(real*real + imag*imag).
Stefan
voice
this.
How
the
many
My pic24f controller has a 22k program memory and 8k data memory. I need to implement a fft with this hardware. So please find me a c code for fft which makes the micro controllers performance optimum.
Thanks, Siva
No Google in India??
Meindert
need
fft
But i could not find a one which suits my requirement.
Siva
"sivaramakrishna" wrote
Look for any FFT code on the web like fftw (google+fftw) Don't forget to put an antialiasing filter or you will get spectrum overllaping!
For voice signal 3kHz filter should be fine, and you should sampe with at least 7kHz ! Number of samples depend on you're wanted physical spectrum resolution. For radix-2 algorithm try 64/128/256 and see what suits you best.
Also, it would be great to learn basics of DSP :) Greetings from Croatia from a student!
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