c# - DSP FFT fundamental frequency wav file -

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i have fft algorithm in c# , generate sine wave in buffer @ frequency of 440, fs=1600 , window length of 2048.

before sending signal fft, double window length , put imaginary values( 0es) between buffer data. after fft, compute amplitude , take index of max amplitude , multiply bin size. , works returns 442 hz :)

now put same generated sine recorded .wav file matlab. when run fft c# returns 884 hz double expected. why?.

i checked .wav file audacity , got 440 corrected value.

so ideea why got doubled value?

i figured out it, seems didn't read wav file correctly.


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