in the past Achilleas wrote:-------
There are a couple of potential problems with your flowgraph:
- the trellis encoder outputs unpacked bytes. For example, if your FSM
output cardinality 4 then it outputs 2 useful bits per byte.
Are you sure you are handling this the right way at the packet encoder?
I do not know how that block works but you should check it.
however, the main problem is the following
- You need to substitute the “trellis viterbi” by the “trellis viterbi
block and input as parameters the kind of “distance” metric you want and
corresponding constellation, etc. To do that you need to know what is
output of the packet decoder…
I have never worked with packet en/decoder so i cannot help with these.
-------------end of quote.
well, I first want to thank you, because it success. (The problem is
I did simplify the example: a source, a trellis and a viterbi combo.
Next, change the types for bytes.
Next use ‘packed to unpacked’ in the head.and ‘unpacked to packed’ in
tail of the flow.
i test with noise source the trellis, trellis-D8psk and trellis-DBPSK.
trellis-DBPSK in noise is better than trellis in noise .
but trellis in noise is better than trellis-D8psk in noise.
DBPSK Hamming distance=2.
trellis Hamming distance=sqrt(2).
the snapshot…where are the snapshot?