Howtosignalprocessing
What is zero phase?
1. A filter for which the phase shift is zero for all frequencies. Zero-phase filters are anticipatory and hence are not physically realizable, i.e., half of the energy arrives before the time reference so that one gets output before the input arrives.
What is zero phase response?
A filter has a zero-phase response if its frequency response is real-valued. A zero-phase filter must have an odd-number of samples in its support with the origin at the center. If the filter has real coefficients, then the impulse response must be symmetric about the origin, i.e. h(n) = h(-n).
How to use filtfilt function in matlab?
y = filtfilt( b , a , x ) performs zero-phase digital filtering by processing the input data x in both the forward and reverse directions. After filtering the data in the forward direction, the function reverses the filtered sequence and runs it back through the filter.
