normalized filter coefficients (farsheed )


Subject: normalized filter coefficients
From:    farsheed  <tfarsheed(at)YAHOO.COM>
Date:    Tue, 19 Apr 2005 10:56:49 -0700
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Hello, I have been trying to implement tunable biquad bandpass/bandstop filters using an allpass filter on a fixed point DSP (TI-54x) and have run into the problem of the filter going unstable when the z^-1 term goes over 1. I am using a direct form II implementation, but have heard that there is a way to normalize the coefficients (normalized ladders??) to keep the coefficients less than 1. The z^-1 term looks like B(1+alpha), where B controls center frequency and alpha controls bandwidth. I was wondering if anybody could point me to some documentation regarding this, online or otherwise? Thanks, Farsheed Student, University of Illinois __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com


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Electrical Engineering Dept., Columbia University