MATLAB: How to determine b and a values for a data signal when using filter() function

coeffiientsfilterfilter coefficientsfilter fucntion

Hello,
How do I determine the suitable b and a values when using filter function to filter a data signal?

Best Answer

Use any of the filter design functions that produce transfer function output.
However the transfer function coefficients can create unstable filters. It is always best to have the filter functions create zero-pole-gain (z,p,k) representations rather than transfer function representations, then use the zp2sos function to convert them to second-order-section representation to produce robust, stable filters. The filtfilt function can use them, as well as digital filter objects (such as thouse produced by lowpass, bandpass, and similar functions) to filter signals.
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