how to find FIR filter specs from coefficients

hello everyone,

I currently have a filter designed a long while ago and i only have coefficients.

i know its a FIR BPF.

i want to find the specs of the filter so i can in theory input these specs to a filter building function and recieve the exact same coefficients.

any help would be appreciated

thank you

Answer 1

[Star Strider]

I assume your filter is a discrete (digital) filter, not a continuous filter.

Probably the easiest would be to use the Signal Processing Toolbox tf2zpk function. It will give the zeros, poles, and gain variables. Another option is zplane to check on their locations in the unit circle.

If the filter is a continuous filter, the Control System Toolbox functions would be more appropriate.

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[Iftach Zairi]

didnt really work for me because its a long filter(633 coefficients). also, i dont know how to reinsert those into a filter function to check my results. in the end i need to write to a file the specs of the filter for others to reproduce in the future.

i appreciate the help though.

thank you

[Star Strider]

As for creating a filter from the [z,p,k] results, you can do the inverse and use zp2tf to create the coefficient vectors.

The only other option I can offer is to simulate the filter using freqz. You can then get the necessary characteristics from the magnitude and frequency outputs (if you request them) that you can then analyse (passband, stopband, stopband attenuation, and others) in order to synthesize your filter.

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