digital filter parameters selection using matlab

hi, i think matlab should have the function that i need to figure out the digital filter parameters: 1. i have this fitlers form: 1 + a*z^-1 +b*z^-2, and i want to know a and b; 2. i have a complete known input sequence, and i know the output of this fitler has the form of 1+ c*z^-1 +*z^-2 (c is unknown, which is my final care number after a,b are known based on input and ouput). please teach me if you guys know how to it in matlab. thanks a lot. jeff

Answer 1

[Star Strider]

The firls function is likely what you’re looking for. The fircls and fircls1 functions might also be helpful. (I rarely use them, so I have little experience with them.)