signal processing - C program fast fourier transform error advice -


this question has answer here:

so bit confused error having taking fft of sine wave. fft function given us; function has fill in first input array 256 samples of magnitude second input array 0. function takes fft in place , returns index of peak frequency.

so not sure how convert returned index actual frequency of input wave. equation given frequency = samplefrequency * index / n. tried sample frequency 3 times maximum input frequency , follow guidelines still not getting correct frequency results. advice helpful; thanks!


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