Re: [Discuss-gnuradio] Filter in rational resampler

[Marcus D. Leech]

On 07/30/2014 12:42 PM, Daniele Nicolodi wrote:
> Hello,
>
> I was studying the code of the rational resampler block in
> gnuradio/gr-filter/pythoin/rational_resampler.py and I have a doubt
> about the low pass filter generated by the design_filter() function.
>
> It seems that the generated filter does not take into account the
> decimation factor. Is that correct? I don't see how this may result in
> the correct anti-aliasing filter when it is applied by
> rational_resampler_base_xxx.
>
> Can someone point me to a relevant explanation?
>
> Thanks a lot. Cheers,
> Daniele
>
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The filtering happens *before* resampling.  It has to, or you end up 
with aliases.



--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org