I have managed to implement both forward and inverse FFT transforms in C#. And, i tested them by taking signal both ways and got the real part after iFFT equals the original signal.
Now , I have taken the same signal in frequency domain and changed both magnitude spectrum as well as phase. Then, i have taken the complex number of both outputs to iFFT.
The complex number I got now, has values on the imaginary part(no longer zeros as the original signal case).
How i can rebuild time signal from this IFFT complex output?
Thanks,
The DFT $X[k]$ of a real-valued signal $x[n]$ satisfies
$$X[k]=X^*[N-k]\tag{1}$$
where $N$ is the DFT length and $*$ denotes complex conjugation. When you modify $X[k]$ you must make sure that the modified DFT also satisfies $(1)$, otherwise your time domain sequence will be complex-valued, which probably does not make sense for your application.