how to reconstruc a signal from its modified discrete fourier transform?

Dear all I need to modify the discrete Fourier transform coefficients and then inverse it from frequency domain to time domain. suppose the signal is sig and the modification vector is R. I first determine the Fourier coefficients by fft function: dft = fft(sig); %modify Fourier coefficient DFT = R .* dft; now the question: is there any signal in time domain that its Fourier coefficients be DFT. if the answer is yes, how can I evaluate it? thanks

Answer 1

[Star Strider]

You seem to have defined a filter in the frequency domain. See theSignal Processing Toolbox fftfilt (link) function for details.