Re: [Discuss-gnuradio] New sources, general questions

[Eric Blossom]

On Wed, Mar 10, 2004 at 05:26:37PM -0600, David Carr wrote:
> Hello all,
> 
> I'm currently doing some SDR research and I'd like integrate some parts 
> of my project with the GNU Radio base for mutual benefit.  I'm having 
> some difficulty understanding the general model of the GNU Radio 
> framework.  I like the source/sink architecture very much, it seems a 
> very good way handle the data flow.  I however, haven't be able to 
> resolve the differences between Gr and Vr type items.  What 
> differentiates these?

The good news is I'm doing some major house cleaning on the code base.
The bad news is it isn't done yet.  The Vr stuff is stuff we inherited
from the MIT spectrumware code base.  Some of it has had reasonable
maintenance.  Other parts of it is pretty broken.  The Gr stuff is in
much better shape, and when it appears there's a module with similar
functionality in both versions, use the Gr one.  All the Vr stuff will
be gone with in a couple of weeks.

> Also, I'm using an NI AT-MIO-16E-1 aquisition card in a "capture server" 
> that streams raw data in over a TCP connection.  I'd like to create a 
> TCPSource in order to integrate this setup (and other TCP network 
> sources) with the current framework.  I can do basic unix style netwok 
> programming but what might I need to do as far as buffering is 
> concerned?  My data source outputs 1.25M 16 bit samples per second, 
> continuously. 

Should be no problem.  The data rate is plenty low.  We run the USRP
at 32MB/sec, the MC4020 A/D card at 40MB/sec.  I want to mention that
we're moving away from the template based Gr/Vr modules into something
that works just as well or better, is easier to debug, and works
better with Python.  GrFileSource uses the new style.  Take a look at
it.  I think you'll find it easy to build a GrTCPSource in the same
style.

> Lastly, what good "intro to the framework" documentation is out there 
> that I might have missed?  I would like to become much more familiar 
> with the goings on of GNU Radio.

As soon as I'm done whacking the code, I'll take a crack at an "intro
to the framework".  I figure at a minimum we need information on how
to build new primitives as well as how to use them.  If you aren't
familiar with programming in Python, now's a good time to start :-)

I could definitely use some help putting together the docs, and would
be delighted to answer questions and build examples.

> Thanks for your time,
> David Carr
> Rice University

Thanks for your interest!

Eric