i'm trying to filter a signal with a FFT. I window each block of signal (i use a 4096 points signal) and then remove some high frequencies by just multiplying the magnitude response.
the result is : the more i remove highs, the more i have glitches.
I know it's bad to EQ directly with the FFT but i just want to know why there are some glitches
i tried to zero the DC, i tried to window another time the input window by a short amount (maybe not the clever thing to do).
i have less clics when using a Nutall window, compared to a Hamming or Hanning, and the clics seems to appear every FFTSize/2 samples
so, why clics? and what is the remedy?
thank you gentlemen.
edit: i've searched everywhere without getting a proper solution.
edit 2 : you can try this matlab program, (i'm not very sure about the filtering part but if it's wrong correct it and it should glitch all the way) http://pastebin.com/8tBmjNqG