Re: [Discuss-gnuradio] A longish-term drift study of the USRP/DBS_RX combination

[Marcus Leech]

Matt Ettus wrote:

> Very cool.  Thanks for doing all this development on the RA receiver.
> I'm very excited to see where it goes.
>
> Matt
>
>
>  
Now that I understand a bit more of the internals, it's really starting 
to gell for me.

Some things I'd like to add:

      o interference stopping

      o recording the FFT results, without having to define a whole new 
chain (I'm at 50-60% CPU already!!)
         [I might pull the same trick here that I did with 
ra_stripchartsink--define a "calibration" function that
           can record data as a side-effect.  I'd simply make an 
ra_fftsink that does this].

      o Possible integration of PyFits (although whether it makes sense 
to do it in real time remains to be seen)

      o Deriving the total power from the FFT results, eliminating the 
parallel total-power chain

It would be interesting and cool at some point to demonstrate an FX 
correlator using a pair or trio (or quad, or pentad :-)
 of USRPs with appropriate front-ends and antennae.  In an FX 
correlator (which is a style that's currently in vogue)
 you compute the FFT before computing the various cross products.  It 
has more manageable data structure than
 X-F correlators for RA use.  You can see that you can martial the 
various FFT bins off to different CPUs for
 further processing in an FX design, and thus control, to some extent, 
the herculean data flow that occurs in
 these RA systems...


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