Re: [Discuss-gnuradio] How to decode the convolutional code in the GRC

[Ben Reynwar]

You're right my suggestion won't work since the demodulation blocks
output bits, and the viterbi_combined block expects complex symbols.
I'll try again.

How about something like the dbpsk block
(gnuradio-core/src/python/gnuradio/blks2impl/dbpsk.py) but with the
constellation_decoder replaced with trellis_viterbi_combined.  If I
was going to do this I wouldn't try to do it in GRC, but it is
probably possible.

Ben

2011/3/11 intermilan <address@hidden>:
> Ben:
>      Thanks for your reply.I knew that block you mentioned.And I know if I
> use the block chunks_to_symbols after the trellis_encoder,that parameter
> constellation should be the same as the parameter symbol_table in the
> chunks_to_symbols.And  I think this is TCM.
>      But in my flow graph,there is no chunks_to_symbols block,then I do not
> know how to set that parameter, so I do not know how to decode the data.Do
> you know how to set that parameter constellation in the block
> trellis_viterbi_combined if I used this block in my flow graph?
>
>   inter
>
>
>> Date: Thu, 10 Mar 2011 22:33:36 -0700
>> Subject: Re: [Discuss-gnuradio] How to decode the convolutional code in
>> the GRC
>> From: address@hidden
>> To: address@hidden; address@hidden
>>
>> You probably want to use the trellis_viterbi_combined block.
>>
>> The documentation for the trellis blocks is in
>> gnuradio/gr-trellis/doc/gr-trellis.xml.
>> (if you have xmlto installed then an html file is also built.)
>>
>> Ben
>>
>> 2011/3/10 intermilan <address@hidden>:
>> > Hi all:
>> >       Now I want to use the Trellis_encoder block in the GRC to make an
>> > example for the convolutional code.In my opinion, I use Trellis_encoder
>> > to
>> > produce the convolutional code,  then make the convolutional code
>> > through
>> > the modulator and demodulator(such as DPSK), finally use some block to
>> > decode the convolutional code to get the original data.But after the
>> > data
>> > get out the demodulator,I do not know how to decode it.
>> >      Here is the flow graph I used:
>> >
>> >
>> > vector_source->throttle->Packed_to_Unpacked->Trellis_encoder->Packet_encoder->DPSK_mod->DPSK_demod->Packet_decoder->?
>> >     Can anyone tell me which block I should use after the Packet_decoder
>> > to
>> > decode the convolutional code?
>> >
>> >
>> > Thank you in advance.
>> >
>> > _______________________________________________
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>> > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>> >
>> >
>
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