Re: Xlating FIR filter delay

[CEL]

Ah, no!

So, what you're seeing is no processing delay caused by our
implementation of the xlating FIR filter, but simply *group delay*,
which every linear system has.

I don't know your background, so it's a bit hard to recommend some
literature, but group delay would be covered in a "signals and systems"
text book.

> Guess I've found the answer:
> (len(filter_taps) - 1) / 2

That is true ONLY if your filter has linear phase. It has linear phase
iff it's symmetric to the center tap.

Best regards,
Marcus

On Thu, 2019-12-19 at 14:08 +0000, Angilberto Muniz Sb wrote:
> Yes Marcus, I'm interested in the "excess" delay, thats why I need to cancel 
> the group delay.
> 
> Guess I've found the answer:
> 
> (len(filter_taps) - 1) / 2
> 
> Will try it..
> 
> 
> Angilberto.
> 
> 
> Em quinta-feira, dezembro 19, 2019, 9:16 AM, Müller, Marcus (CEL) 
> <address@hidden> escreveu:
> 
> > Hi Angilberto,
> > 
> > am I right to assume that you already are considering the group delay
> > of the filter that you specified and there's "excess" delay beyond
> > that?
> > 
> > Best regards,
> > Marcus
> > 
> > On Wed, 2019-12-18 at 19:59 +0000, Angilberto Muniz Sb wrote:
> > > Hi all,
> > > 
> > > I have a dual tone signal that I down convert and split into two common 
> > > frequency signals with the Xlating-fir filter. So far so good. 
> > > 
> > > However I noticed there is a phase shift between the signals generated (I 
> > > assume this is due the filter delay). I have to compensate for that.
> > > 
> > > The question: How to determine or estimate that delay?
> > > 
> > > Thank you,
> > > 
> > > 
> > > Angilberto.

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