[Scilab-users] Define numerator and denominator of transfer function as variables in Xcos (DLR block)

[Nikolay Strelkov]

Anybody?
Dear Tim, do you have any idea?

--

*With best regards,Ph.D., *


*associate professor at MPEI
<http://mpei.ru/lang/en/Pages/default.aspx>,IEEE member,maintainer of
Mathieu functions toolbox for Scilab
<http://atoms.scilab.org/toolboxes/Mathieu/>,Nikolay Strelkov.*

2017-03-23 14:27 GMT+03:00 Nikolay Strelkov <n.strelkov at gmail.com>:

> Dear all!
>
> I'm playing with simple digital filtering in Xcos 5.5.2.
> I have two filters - low-pass and high-pass, connected in series.
>
> Xcos does not have convolution block.
> So I write FIR transfer function
> <https://ccrma.stanford.edu/%7Ejos/fp/FIR_Transfer_Function.html>
> manually from impulse response function.
> I get impulse response functions from wfir function.
>
> Let's assume that we have two simple filters with impulse responses:
> h1 = [0.3741957    0.3741957]; // it's low-pass filter from h1 =
> wfir("lp",2,[.2 0],"re",[0 0])
> and
> h2 = [- 0.1870979    0.8  - 0.1870979]; // it's high-pass filter h2 =
> wfir("hp",3,[.1 0],"re",[0 0])
>
> I convert them to DLR <https://help.scilab.org/docs/5.5.2/en_US/DLR.html>
> SISOs and get:
> H1(z) = 0.3741957*z^-1 + 0.3741957*z^-2 = ( 0.3741957*z + 0.3741957 ) /
> (z^2);
> H2(z) = -0.1870979*z^-1 + 0.8*z^-2  - 0.1870979*z^-3 = ( -0.1870979*z^2 +
> 0.8*z  - 0.1870979*z ) / (z^3);
> and place their numerator and denominator to the corresponding DLR blocks.
> Model is in attachment. It's an illustration, not real world example.
>
> I have a question. How I can automate the aforementioned process
> programmatically?
> I tried to create numerator and denominator with poly function and as
> strings, but Xcos does not support these types in DLR settings.
>
> --
>
>
>
>
> *With best regards,Ph.D., assistant professor at MPEI
> <http://mpei.ru/lang/en/Pages/default.aspx>,IEEE member,maintainer of
> Mathieu functions toolbox for Scilab
> <http://atoms.scilab.org/toolboxes/Mathieu/>,Nikolay Strelkov.*
>
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