Discrete low-pass filter

Hi community!

I have created a Matlab function block. Then I have set its sample time equal to "Ts" (100e-6). After that I implemented a simple low-pass filter code using this block, the results are different from when I build the filter using the "1/s" and "gain" blocks of Simulink. The transfer function of the filter is:

Y/X=1/(1+sTc)

I have implemented it by applying the backward Euler discretizing method as :

Y(k)=(Ts/(Ts+Tc))X(k)+(Tc/(Tc+Ts))Y(k-1)

where X is a sinusoidal function given from outside of the Matlab function block.

Is it something wrong here?

Regards,

[Mathieu NOE]

hi

you can use c2dm to discretize analog filters

also se attached some typical digital filters implementation

[lionel messi]

Thank you for the reply and the files!

I'm gonna try these..

Regards