[PD] from poles/zeros to biquad coefficients - how to? (something like max's z-plane)

[Simon Wise]

On 24/09/13 21:46, Funs Seelen wrote:
> On Tue, Sep 24, 2013 at 3:35 PM, Alexandre Torres Porres
> <porres at gmail.com>wrote:
>
>> so you're basically saying all i need to use is use only the real part,
>> right?
>>
>
> No, I meant that I have the idea that the imaginary part in the calculated
> coefficients will disappear automatically if you add complex conjugates for
> all poles and zeros, probably when somehow i^2 gets -1 somewhere. But I
> must say I'm not a mathematician and not sure at all.

indeed it will ... a conjugate is the number with the imaginary part negated ... 
so adding a number and its conjugate will certainly end up with a real part only.


Simon