Re: [Discuss-gnuradio] designing filters: remez?

[Eric Blossom]

On Fri, Jan 11, 2008 at 01:34:18PM +0100, Martin Braun wrote:
> On Thursday, 10. January 2008 20:01, Patrick Strasser wrote:
> > method functions. Is there something bad about designing filters with
> > the Remez method? I thought it would be clever to constraint the filter
> > to a number of coefficients, as this parameter is most important for
> > processing speed.
> 
> I haven't had a look at the code, but in general the Remez method is always 
> superior. In fact, the last course I had on filter design taught me the 
> window method is only really used in quick-and-dirty filter design and in 
> teaching, because it's so simple to explain (plus, it's easier to code).
> 
> > Moreover, what would bring faster results, a designer using the window
> > method or one with the remez method?
> 
> I doubt the window method can be beaten in terms of speed, as it's only an 
> FFT 
> and a multiplication, but I don't know how much faster it is.
> However, usually the filter design is not in the time critical part of an 
> application, whereas the number of taps has direct influence on performance.
> Given the choice, I'd say use remez when possible.
> 
> martin
> 
> -- 
> Martin Braun
> Institut fuer Nachrichtentechnik
> Universitaet Karlsruhe
> 
> http://www.int.uni-karlsruhe.de

The existing GNU Radio wrapper around the remez primitive needs help.
IIRC only the low_pass case works.  Perhaps one of you guys can take a
look at it.  Creating a few test cases would be great too ;)

Eric