> Having only real coeffecients for biquad forces the poles (zeros) to take this form.
yeah, that makes sense. The tricky part seems to be how a complex conjugate pair does that too. Is it because you'd add them up and then the imaginary part becomes zero? That's what I can think of... 2014-07-25 10:49 GMT-03:00 Claude Heiland-Allen <cla...@mathr.co.uk>: > On 25/07/14 14:36, Alexandre Torres Porres wrote: > >> it's accurate to say that [biquad~] is a real-valued 2-pole/2-zero filter. >>> >> >> but why, if the poles and zeros can have complex values? >> > > If the poles (zeros) occur in as a complex conjugate pair (with identical > real parts and opposite imaginary parts), or both poles (zeros) are real, > then the filter will have real output for real input. Having only real > coeffecients for biquad forces the poles (zeros) to take this form. > > > Claude > -- > http://mathr.co.uk > > > > _______________________________________________ > Pd-list@lists.iem.at mailing list > UNSUBSCRIBE and account-management -> http://lists.puredata.info/ > listinfo/pd-list >
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