On May 12, 8:28*am, "v333k" <v3...@yahoo.com> wrote:
> Hi all,
> I have a relatively basic question about applying a bilinear
> transformation using MATLAB. *I am familiar with the bilinear function,but
> the question states the following:
> apply the bilinear transform to Ha(s) in order to obtain H(z) such that w1
> = pi/4 radians.
>
> Ha(s) = 20/(s^4 + 2s^3 + 8s^2 + 20s + 20)
>
> my question/confusion is where does the w1 play a role in this?
>
> thanks in advance!

Perhaps this question has some context around it that you are not
posting here. In general the bilinear transform does a mapping between
Laplace and z-domains where 0 -> 0 and infinity -> pi and then a third
point is adjustable in the sense of where you do the mapping. I.e.
this is the "c" or whatever stadard variable you see in the bilinear
transform. s = c (1-z^-1)/(1+z^-1) sometimes the "c" is written as 2/
T where "T" is the sampling period. If the Laplace expression is
normalized to 1 rad/sec, then "c" is simply cot(pi*f) where "f" is the
normalized digital frequency that gets mapped to 1 rad/sec.

Clay