[Discuss-gnuradio] trellis help please

[smith mark]

Hi everyone,

I want to implement convolutional coding using the trellis block. I don't want to use any modulation scheme or anything else after the encoder. The flow graph I want is shown below

vector source---->trellis encoder----> viterbi or any decoder------->sink 

Part of the code is shown below

----------------------------------------------------------------------------

src_d = (1,0,1,0,0,0,1,1,0,0,1)

sorc = gr.vector_source_b (src_d)  //source

encoder = trellis.encoder_bs(f,0)    //encoder

s2f= gr.short_to_float()                 

dec=trellis.viterbi_s(f,len(src_d),0,-1)  //decoder

dst = gr.vector_sink_s ()                   //sink

tb.connect (sorc,encoder,s2f,dec,dst)

return(dst.data())

----------------------------------------------------------------------------

 When I run the above flow graph I get nothing just empty, ( ), list.

I am using "awgn1o2_4.fsm" file. I got the correct result after encoder. I can't use the trellis.metric or trellis.viterbi_combined_X to implement decoder as I am not using any modulation :( .

Can anybody please help me in this ??

Regards

Smith