I think a symbolic z-transform would be a very welcome addition to Maxima.
I don't know if commercial Macsyma ever included z-transform routines, but
if so it should be possible to port them to Maxima (assuming that you can
obtain the source code).
On 1/27/07, Ryan Krauss <ryanlists at gmail.com> wrote:
>
> Is anyone aware of Maxima functions to find the z transform of a
> function of time? I need to convert some transfer functions from the
> Laplace domain to the z domain and include the effect of
> sample-and-hold circuitry. One way to do this is to inverse Laplace
> the transfer function divided by s and then z transform, and then
> multiply by (1-z^-1). I know that Maxima has inverse Laplace, I would
> just need to be able to do a z transform to make it all work.
>
> The z transform is an infinite sum, so perhaps this is not a big deal
> for maxima:
> X(z)=sum x(kT)*z^-k where k goes from 0 to infinity and T is the
> sample time to move from continuous time t to discrete time kT.
>
> Thanks,
>
> Ryan
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