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Re: [Discuss-gnuradio] convolutional code via gr-trellis
From: |
Achilleas Anastasopoulos |
Subject: |
Re: [Discuss-gnuradio] convolutional code via gr-trellis |
Date: |
Thu, 22 Feb 2007 20:54:55 -0500 |
User-agent: |
Mozilla Thunderbird 1.0.2 (Windows/20050317) |
vincenzo,
this is NOT correct:
what is the purpose of the repacker?
the encoder in your case outputs bytes with values in {0,1,2,3}
these need to be mapped to your constellation (QPSK), not to be packet
into bytes.
I am surprised that this does not result in an error
within the chunk_to_symbols block...???!!!
f=trellis.fsm("/root/MAIN/soft/gnuradio/gr-mystuff/finite_state_machine")
file_chunker=gr.packed_to_unpacked_bb(1,gr.GR_LSB_FIRST)
convolutional_encoder = trellis.encoder_bb(f,0)
self.connect(file_source_bytewise,file_chunker,convolutional_encoder,symbol_mapper)
Achilleas
---------------
Hi, thanks again Achilleas for suggestions and help,
so far I've tried this for the convolutional 1,2 code.
this is the file for setting up the finite state machine
2 4 4
0 2
0 2
1 3
1 3
0 3
3 0
2 1
1 2
does it make sense?
and this is the code for connecting the encoder into the flow grpah
file_chunker=gr.packed_to_unpacked_bb(1,gr.GR_LSB_FIRST)
f=trellis.fsm("/root/MAIN/soft/gnuradio/gr-mystuff/finite_state_machine")
repacker=gr.packed_to_unpacked_bb(2,gr.GR_LSB_FIRST)
convolutional_encoder = trellis.encoder_bb(f,0)
self.connect(file_source_bytewise,file_chunker,convolutional_encoder,repacker,symbol_mapper)
this bringrs out a spectrum picture which is significantly different
than the one without the encoder... much more "squared"
am I going the right way?