Trellis imported on GRC

Josh,

I think the “trellis” part of GRC is ready for prime time.
All my tests work so far and produce the expected results.

I am attaching the following files:
trellis.py (all grc trellis defs)
init.py
Conversion.py (I spoted a bug in the chunks_to_symbols block and I
corrected it)
Sinks.py (I added the “numerical display block that Martin D.
developed–is currently part of the grnuradio trunk”)

also attached find an example graph with corresponding help files
that tests a simple convolutionally encoded QPSK system.


Let me also take a minute and thank you for your contribution. I believe
is very important especially for those of us who need to educate
students: with GRC a student can start using gnuradio in less than a
week! I am definately planning to test this hypothesis over the summer
with a group of undergrads.

My wish list for GRC at this point includes:

  1. A way to build hierarhical block diagrams, ie, group a bunch
    of blocks together and define a new block so I can reuse it within GRC.

  2. global variables of type string and vector
    (so that I can define globally some filenames and some constellations
    that are used in multiple blocks).

Thanks
Achilleas