Re: [Discuss-gnuradio] serial_to_parallel and fft_v{f,c}c

[Patrick Strasser]

Eric Blossom wrote:
> On Thu, Mar 16, 2006 at 09:45:05PM +0100, Patrick Strasser wrote:
> > What is serial_to_parallel doing?
> > Why is this needed?
>
> The fft_v{f,c}c block is defined to consume and produce a stream of
> vectors.  The size of the vectors must be equal to the FFT size.
> serial_to_parallel (also known as: serial_to_vector) converts a stream
> of items into a stream of (fixed length) vectors of items.

I suppose the underlying flowgraph system uses block processing too, but 
here we need chunks of a certain and fixed (so to speak "const") size.

Is there anywhere a document or mail describing the data types in an 
overview?

> > What is the window flag (3rd parameter) in fft_v{f,c}c for?
>
> It specifies the window to be applied to the data prior to computing the
> FFT.  See any DSP book for the background. 
> http://comsec.com/wiki?SuggestedReading
> Lyons' book is a good place to start.

Windowing is clear to me, but I wasn't able to read the python datatype 
or gnuradio window type from the C++ .h file. I suppose it's something 
like gr.firdes.WIN_RECTANGULAR or a vector/list of window coefficients, 
but I could not figure out exactly until now. Any hints? ;-)

> > What would be the best way to document all this in a nice 
> > end-user-compatible way? (I suppose users should be able to do their 
> > programming in python with some form of documentation that is _not_ C++ 
> > source code)
>
>
> There are currently the doxygen generated C++-centric docs.
> http://www.gnu.org/software/gnuradio/doc/index.html

That's my main resource, giving primary hints and leading to the source 
files...

> The output should be python-centric docs in epydoc output format.
> See http://epydoc.sf.net and http://www.stack.nl/~dimitri/doxygen
>
> I've got a patch somewhere in my email that's supposed to do this.
> If you're interested in testing it out, I'll dig it out and you can
> try it.  If it works, we'll apply it.

I'd really like to try this.

You know, I'm hindered in my wiki-I-want-to-add-more-doc behaviour. Good 
docs are essential for beginnerns like me, and people used to the system 
most likely don't see what's _not_ obvious...

Patrick
--
Engineers motto: cheap, good, fast: choose any two
Patrick Strasser <patrick dot strasser at  tugraz dot at>
Student of Telematik, Techn. University Graz, Austria