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

[Nikolay Strelkov]

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>:

> 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>:
>
>> 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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