Image we obtain a fft of a signal and we wish to remove certain frequencies from the signal. I want to fill in zeros after removing certain rows of complex numbers. Filling in with zeros [0, 0, 0, 0] did not work because ifft was absurd. The real part and the imaginary part must be zeroed and it should appear like 0.0000+0.0000i. Is there a way to fill in 0000+0.0000i in desired regions of the FFT of the signal? What command should one use? Basically this is fft filtering.
Say fft(A) = [-0.0708535039155114 - 0.00736177322883826i, -0.0700055929768761 - 0.0329196686985671i, -0.0593736872430442 + 0.00109491019902367i,
-0.0435002106533236 + 0.0325121703659659i, -0.0605346303385998 - 0.000499071340404484i]
How should we convert that into by removing certain complex numbers and convert them into zero complex numbers?
[-0.0708535039155114 - 0.00736177322883826i, 0.000000 +0.0000000000i, 0.000000 +0.0000000000i, 0.000000 +0.0000000000i,- 0.000499071340404484i]