Re: [Discuss-gnuradio] Coherent de-dispersion

[Marcus D. Leech]

On 07/01/2010 07:28 AM, Bruce Stansby wrote:
> Hi Marcus
>
> I havn't quiet got my head around coherant dedispersion myself, I use in 
> coherant. Basically as far as I'm aware it does all the delays in fourier 
> space. It is generally far superior to the standard incoherant method but for 
> searching is ineficient as it can not usually be done in real time across a 
> wide bandwidth.
>   
Yup, I'm well aware of that :-)

> Hence unless your trying to find a signal at a specific DM a blind search 
> usually uses incoherant, unless you have a cluster at your disposal. If you 
> are trying to test if the signal is ther for a specific object and not sure 
> about your disperser then I suggest folding the spectral data at a pulse 
> period, you can then find it in a waterfall plot of your bandpass. 
>
> or else you can try and download DSPSR and use something that is known to 
> work, if you can work out the install.
>
> Regards Bruce
>   
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).

Since I won't have a live instrument to connect this stuff to for
*months* (http://www.sbrac.org),
  I wondered if anyone had thought of test strategies for testing a
coherent de-disperser prior
  to "live" tests using real objects.


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