My question is about the action of a bandpass filter. First, I have a temporal signal. I convert it in a spectral signal via a FFT. Now, I want to apply a bandpass filter on that spectral signal. But my question is : how to do it ?
My temporal signal is a real signal so, I understand how to multiplicate by a coefficient. But my spectral signal is complex so, what do I have to do ? Multiplicate the real part and the imaginary part by the coefficient ?
Thank you for your answers,