Consecutive filtered blocks with filtfilt

1. What is the difference between filtfilt and filter?
2. What does filtfilt mean in matlab?
3. What is zero phase filtering?
4. What is filtfilt in Python?

What is the difference between filtfilt and filter?

You can see that although filter() and filtfilt() both remove the high frequency noise, the use of filter() introduces significant phase delay. filtfilt() has zero phase delay. Further, at t=0, the output of filter() starts at 0, whereas the output of filtfilt() has matched the initial conditions exactly ².

What does filtfilt mean in matlab?

Description. 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.

What is zero phase filtering?

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).

What is filtfilt in Python?

Apply a digital filter forward and backward to a signal. This function applies a linear digital filter twice, once forward and once backwards. The combined filter has zero phase and a filter order twice that of the original.