Re: [Discuss-gnuradio] Coherent de-dispersion

[Marcus D. Leech]

On 07/01/2010 11:31 AM, Tom Rondeau wrote:
>> Actually, my frequency-domain coefficient generator is based loosely on
>> some earlier Swinburne
>>  code, and then I use the Gnu Radio FFT filter block, after turning the
>> frequency-domain
>>  coefficients into time-domain ones (for some bizarre reason, the Gnu
>> Radio FFT filter takes
>>  its coefficients in time-domain, rather than frequency domain).
>>     
> (I should probably change the subject, but this is just a quick
> interlude and hopefully won't spawn a long conversation.)
>
> Do you really think that's bizarre? I always think of filter taps
> being naturally expressed in the time domain. But maybe that's just a
> limitation of my background. In the constructor of the fft filter
> block we do the FFT to convert them. Since all of our algorithms
> return the taps in the time domain, it makes sense to me to handle
> both filters the same.
>
>
> Tom
>
>
>   
Oh, I agree that it's in the tradition of Gnu Radio filters.  It's just
that after you've finished reading
  paper after paper about FFT filters for de-dispersion, with everything
being expressed in the
  frequency domain, it's a bit jolting to find that the FFT filter takes
"taps" in the time-domain.

Perhaps "bizarre" was too stong a term :-)

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