[PD] biquad~ with elementary filters [was: Re: dinosaurs ...]

[Frank Barknecht]

Hallo,
Damian Stewart hat gesagt: // Damian Stewart wrote:

> Frank Barknecht wrote:
> > Hallo,
> > Frank Barknecht hat gesagt: // Frank Barknecht wrote:
> > 
> >>> 1*z^2 - fb1*z^1 - fb2 = 0
> >> zb = (-fb1 +- sqrt(fb1*fb1 - 4*fb2)) / 2
> > 
> > Sorry, the one above is wrong, of course. Given the minus-signs in the
> > original transfer formula it should be:
> > 
> > zb = (fb1 +- sqrt(fb1*fb1 + 4*fb2)) / 2
> > 
> > if I'm right.
> 
> see, Chuck, if Frank gets it wrong what chance do i have? ;-)

;) 

Attached is a patch which shows one of my failed attempts to try 
something to get a real/imaginary pair out of the formulas I derived.
It's completely wrong, but might illustrate our problems.

Ciao
-- 
 Frank Barknecht                                     _ ______footils.org__
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