Re: About the derivation in firls.m

[Quentin Spencer]

Yes, I’m still here. It has indeed been a very long time. I’ll try to take a look at the code and see if I am able to answer your question.

On Apr 13, 2017, at 10:19 AM, Nicholas Jankowski <address@hidden> wrote:

On Apr 13, 2017 11:11 AM, "je suis" <address@hidden> wrote:

Hello everyone

And I hope this isn't the wrong list to send this to. I am trying to
make a small program in C++ about filter design, and I am currently
trying the least-squares algorithm, based on Selesnick's paper (the
same one from firls.m). However, I would like to be able to also make
type iii and iv filters, differentiators and Hilbert transformers,
too, and I was looking through your firls.m file, where I got stuck at
the derivation of "cos_ints2". If it's not too much to ask, can
someone please let me know how did it get from the formula in the
comment to the one in the function calculating "cos_ints2"? I can't
figure it out, not even with wxMaxima by my side.

In the extreme case that my beginner programming skills allow it, I
would also like to be able to make the weights as a linear variable
function, too, so I would guess that the q vector will follow about
the same principles as the b vector, so I would like to try it out,
even if my small program, most probably, will never leave the screen
of my monitor. But, if I get "lucky" (one is allowed to dream), I will
let you know.

Vlad

_______________________________________________
Help-octave mailing list
address@hidden
https://lists.gnu.org/mailman/listinfo/help-octave

The Signal package maintainer is copied on this email, but the copyright notice in firls.m suggests it was written in 2006 by someone else. I cc'd that person here on the chance the email is still valid and they may be able to take a moment to help you out.

Nick J.