Re: Slow varying inputs

On Sun, 2005-03-06 at 22:07 -0500, Sandy Pond wrote:
> On Sun, 2005-03-06 at 18:32 -0500, Daniel Nilsson wrote:
> 
> > I've been playing with different kinds of filters to compare
> > performance, while doing so I found that I could create an IIR filter
> > with a relatively small order (4 for example) that would act as a very
> > efficient low-pass filter. To get the same characteristics using an
> > FIR filter I had to create a much higer order (>30), this makes sense
> > to me. Correct me if I'm wrong...
> 
> Although your question wasn't directed to me I suggest you try comparing
> to a 4 order of the low_pass_filter.c I posted before.
> 
> I attached an example2_low_pass_filter.c which uses 4 poles.
> 
> > 
> > From reading various FAQs I find that one of the concerns with IIR
> > filter over FIR filters is stability. Would that be a concern in an
> > application where I use samples from Comedi ?
> > 
> 
> Since the low_pass_filter.c has no zeros it's always stable and
> guarantied to have unity steady state gain.  The code is very efficient
> as well.
> 
> Regards
> 

Forgot to attach :)