https://ww​w.mathwork​s.com/help​/hdlfilter​/hdl-butte​rworth-fil​ter.html

https://www.mathworks.com/help/hdlfilter/hdl-butterworth-filter.html

I cant held Modelsim figure from above link.

Can you help me?

Answer 1

[Stephan]

Try the link from the documentation of R2017b:

https://de.mathworks.com/help/releases/R2017b/hdlfilter/examples/hdl-butterworth-filter.html

You should always use the documentation that belongs to your release - if you start on the documentation site, you allways see the latest release.