Re: [dspsr-users] problems with dspsr on 1-pol DFB search mode data

[Scott R. <sr...@nr...>]

Hey Marta,

I know that the 1-bit format changed sometime over the last couple 
years.  The bit ordering in each byte was reversed (i.e. going from LSB 
to MSB first, or vise versa).  I doubt that that would make this issue, 
but it is hard to tell.

Have you tried folding the data with PRESTO?

Scott

On 05/05/2017 03:45 AM, Marta Burgay wrote:
> Dear all,
>
> it looks like the most recent version of dspsr fails to fold search mode
> data recorded with the DFB (at both Parkes and the Sardinia Radio
> Telescope) with 1 polarization.
>
> In attachment you can see an example of what happens folding the same
> data file with the same set of ephemeris with an old version of dspsr
> (installed through PSRsoft, I believe, in 2015) and with the newest
> version.
>
> I did a few tests with SRT data (1-pol 1-bit, 1-pol 2-bits) and PKS data
> (1-pol 1-bit, 4-pol 8-bits) taken in search mode wih the DFB. The latest
> dspsr works fine only on the latter (even though the results are still a
> little better with the old dspsr [pdmp SNR 16 vs 15; first channel
> saturated with the new dspsr]).
>
> I tried both with polyco and predictor and using an ephemeris file or
> giving P and DM directly. Nothing changes.
>
> I'm not sure whether the problem is directly related to dspsr or if it
> depends on psrchive. For SRT data, in fact, I used to install the
> development version of psrchive, before installing dspsr. This solved an
> issue (a warning about an itoa_code not found) that now, with the
> currently available versions of psrchive and dspsr, is back.
>
> Is anyone else having the same problem? Any idea of what can be going on?
>
> Thanks!
>
>     Marta
>
> ---------------------   (> *  ---------------------
> Marta Burgay c/o
> INAF - Osservatorio Astronomico di Cagliari
> via della Scienza 5
> 09047 Selargius (CA)
> Italy
> tel +39 070 71180 249
> fax +39 070 71180 222
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-- 
Scott M. Ransom            Address:  NRAO
Phone:  (434) 296-0320               520 Edgemont Rd.
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