Re: [Discuss-gnuradio] resampler block

[Eric Blossom]

On Tue, Oct 04, 2005 at 10:27:42PM +0200, Stephane Fillod wrote:
> Gang,
> 
> I think this question went unoticed in my audio-jack announce. 
> Is there a resampler block somewhere?
> 
> Last time I heard of a resampler was this summer:
>  http://lists.gnu.org/archive/html/discuss-gnuradio/2005-07/msg00003.html
> but some parts are missing from the gr_rational_resampler block,
> with comments like:
> 
>   # FIXME Bob, please do your magic filter design here
>   return (1.0,) # FIXME

The _fff case mostly works.  Look for FIXME's in
qa_rational_rasampler.py.  However, the automatic filter design
feature is not written.  Without that, you'll need to design the
appropriate filter.  Someone needs to finish sorting out the
filter. For some reason it's failing in the 10,000 element test case.
There is currently qa code for the _fff case.  When it works for all
cases, the _ccc qa code should be written too.

> One of my goal behind the gr-audio-jack module, is to be able to feed
> legacy non-GNU Radio applications like gmfsk, Dream DRM receiver, DttSP,
> etc., with signals from GNU Radio USRP. For that matter, I need
> a resampler block. Can anyone recommand me a gr block to resample, say,
> from 64kS/s to 48kS/s or directly the usrp source at 512kS/s to 48kS/s ?
> Is the gr_rational_resampler finished?

The rational_resampler is what you're looking for.

> In the case of the 512kS/s to 48kS/s ddc, would the gr_rational_resampler
> be able to replace gr_freq_xlating_fir_filter ?

No.  The rational_resampler does not peform frequency translation.

Eric