> Hi,
>
> I'm trying to convert an elliptic transfer function where i have
> knowledge of the poles and zeros (transmission and reflection) into the
> s-coefficients.
>
> is there a matlab routine in which i can do this?
>
> my data is this:
>
> ========= Prototype Pole-Zero Data =========
> (a + jb)
> S21 Poles S21 Zeros S11 Zeros
> -0.1805 0.89515 0 2.02 0 0
> -0.015829 1.013 0 1.308 0 0.99523
> -0.065342 0.9861 0 1.125 0 0.94958
> -0.40772 0.61869 0 1.074 0 0.81465
> -0.57956 1.8358e-016 0 -2.02 0 0.5058
> -0.40772 -0.61869 0 -1.308 0 -0.99523
> -0.1805 -0.89515 0 -1.125 0 -0.94958
> -0.015829 -1.013 0 -1.074 0 -0.81465
> -0.065342 -0.9861 0 0 0 -0.5058
>
> regards,
>
> Phil
Hello Phil,
Just multiply them out. For example:
(s-(-0.1805+j0.89515))(s-(-0.1805-j0.89515)
If you use your roots in conjugate pairs, the resulting polys are real
valued.
(s-a-jb)(s-a+jb) = s^2 -2as + a^2 + b^2
You will likely want to have your result as a few biquads. So using
conjugate pairs for the poles and zeroes, you generate a handful of
quadratic real terms. Then pair up a zero term with a pole term to form
a biquad.
IHTH,
Clay
Reply by Phil Newman●October 13, 20062006-10-13
Hi,
I'm trying to convert an elliptic transfer function where i have
knowledge of the poles and zeros (transmission and reflection) into the
s-coefficients.
is there a matlab routine in which i can do this?
my data is this:
========= Prototype Pole-Zero Data =========
(a + jb)
S21 Poles S21 Zeros S11 Zeros
-0.1805 0.89515 0 2.02 0 0
-0.015829 1.013 0 1.308 0 0.99523
-0.065342 0.9861 0 1.125 0 0.94958
-0.40772 0.61869 0 1.074 0 0.81465
-0.57956 1.8358e-016 0 -2.02 0 0.5058
-0.40772 -0.61869 0 -1.308 0 -0.99523
-0.1805 -0.89515 0 -1.125 0 -0.94958
-0.015829 -1.013 0 -1.074 0 -0.81465
-0.065342 -0.9861 0 0 0 -0.5058
regards,
Phil