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I'm very new in digital signal processing. I have multiple sensors and the way I filters the signals in post processing is:
- take FFT of the signals.
- put zero on out range of interesting frequency (like brick wall filter).
- take IFFT of the spectrum.
I repeat this for each sensor, and compare the phase relation between them in time traces. Thus, the phase must not shift during the filtering process. I wonder the above method distorts the phase or not. Is the ideal band pass filter linear phase?