Re: [Discuss-gnuradio] Newbie Question: Linking with GnuRadio Libraries

[Eric Blossom]

On Fri, Jan 28, 2005 at 05:14:29PM -0500, Bill Peter wrote:
> Hi I'm new to GnuRadio -- but I'm really impressed!  I think this
> might become a revolution as big as the Linux kernel has been to the
> Intel CPU! :-)

Welcome!

> Now, I'm a real novice, but here's my question:  I currently am using
> Matlab to do some DSP on some 10.7 MHz digitized data coming in from a
> receiver and a digitizer.  The receiver is hooked up to an exterior
> antenna used for a physics experiment in the atmosphere.
> 
> I am using quadrature demodulation to downsample the acquired data
> that I am storing on a hard disk.  For this, I use down-mixing with a
> low-pass filter (Butterworth), etc.
> 
> My questions are:
> 
> (1) Can I use the GnuRadio libraries to link in my own "driver" c++
> code to do the same thing I do with Matlab--but now with GnuRadio?

Yes.  If the data is already in a file, you can read it in using
gr.file_source.


> (2) How would I do this?  Can I just write a c++ program that makes
> use of your Quadrature Demodulation class to do it for me:  Would it
> look something like this:
>
> //use GnuRadio libraries
> my_demod = new VrQuadratureDemod( xxx ) ;

Sort of like that.  Your example code looks a lot like the 0.9 code
base.  We're now using the 2.x code base which is a hybrid of C++ for
the low level primitives and Python to glue it all together.

For an overview take a look at:

  http://www.gnu.org/software/gnuradio/doc/exploring-gnuradio.html

Information on how to write new signal processing block in C++ can be
found at:

  http://www.gnu.org/software/gnuradio/doc/howto-write-a-block.html

> and link in with the appropriate libraries?  Does anyone have any
> simple examples/templates and a Makefile ?

howto-write-a-block has examples and templates, etc.

You should also take a look at the stuff in the gnuradio-examples
tarball or CVS for higher level examples written in Python:

  http://comsec.com/wiki?GnuRadio2.X
  http://comsec.com/wiki?CvsAccess


> (3)  Can C++ code link with CC libraries?  I don't know much about Objective 
> C?

Me neither ;-)  

We do link C++ with C and occasionally FORTRAN...

> Thanks for ANY help I get!
> 
> --Guillermo

Eric