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

[Tan Chin Luh]

you're welcome.
anyway it should be a better way to construct the denominator, do let me 
know if you find a better way. :)

rgds,
CL


On 2/4/2017 12:22 AM, Nikolay Strelkov wrote:
> Dear Tan Chin Luh!
>
> Thank you very much.
> It works as expected!
> The problem is solved.
>
> --
> /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./
>
> 2017-04-01 17:23 GMT+03:00 Tan Chin Luh <chinluh at tritytech.com 
> <mailto:chinluh at tritytech.com>>:
>
>     Hi,
>
>     If I understand correctly, you would like to create the filter in
>     Scilab, and directly access from Xcos?
>     if so, u could use the syslin object to do so.
>
>     1. Create the syslin obj
>     h1 = wfir("lp",2,[.2 0],"re",[0 0])
>     h2 = wfir("hp",3,[.1 0],"re",[0 0])
>     num1 = poly(h1,'z','coeff')
>     d = ones(1,size(h1,2)+1)
>     d(1:$-1) = 0
>     den1 = poly(d,'z','coeff')
>     H1 = syslin('d',num1,den1)
>     num2 = poly(h2,'z','coeff')
>     d = ones(1,size(h2,2)+1)
>     d(1:$-1) = 0
>     den2 = poly(d,'z','coeff')
>     H2 = syslin('d',num2,den2)
>
>     2. In Xcos
>     use H1.num in the numerator block for LPF, H1.den in the
>     denominator for the LPF, same for the HPF.
>
>     Hope this helps.
>
>     rgds,
>     CL
>
>
>     On 1/4/2017 9:53 PM, Nikolay Strelkov wrote:
>>     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
>>     <mailto: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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