Matlab sosfilt

1. What is sosfilt?
2. What is sos in MATLAB?
3. What is an SOS Matrix?
4. How does filtfilt work?

What is sosfilt?

y = sosfilt( sos , x ) applies the second-order section digital filter sos to the input signal x . If x is a matrix, then the function operates along the first dimension and returns the filtered data for each column.

What is sos in MATLAB?

The sos function converts the input IIR filter numerator and denominator coefficients into SOS matrix and scale values, and assigns these values to the dsp. SOSFilter object.

What is an SOS Matrix?

sos is an L-by-6 matrix that contains the coefficients of each second-order section stored in its rows. Row vectors b and a contain the numerator and denominator coefficients of H(z) stored in descending powers of z.

How does filtfilt work?

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.