hello everyone... my questions are related to k=7 rate=1/2 decoder and i am thinking of implementing it on FPGA using VHDL.....a general solution will also be appreciated. first question..for 3 bit soft-decision coding is it the encoder that encodes 1 input to 2 3-bit encoded outputs or is it the reciever before viterbi decoder that quantizes the recieved encoded value to 2 3-bit encoded values.....i think it is the reciever...what do you say... second question....if the answer to the first question is reciever then for soft bit decision how do we generate a two 3-bit expected value(total six bit) for the state transition of the encoder at the reciver side while at the trasnmitter side we only generated two 1-bit (total 2 bit)outputs for state transition... third question..how do we calculate metric for soft decision.....and what is soft-bit's impact on path metric and branch metric units of a viterbi decoder.....

# soft bit metric

Started by ●March 22, 2007

Reply by ●March 22, 20072007-03-22

On Mar 22, 6:18 am, "khurram712" <khurram...@hotmail.com> wrote:> hello everyone... > > my questions are related to k=7 rate=1/2 decoder and i am thinking of > implementing it on FPGA using VHDL.....a general solution will also be > appreciated. > > first question..for 3 bit soft-decision coding is it the encoder that > encodes 1 input to 2 3-bit encoded outputs or is it the reciever before > viterbi decoder that quantizes the recieved encoded value to 2 3-bit > encoded values.....i think it is the reciever...what do you say... > > second question....if the answer to the first question is reciever then > for soft bit decision how do we generate a two 3-bit expected value(total > six bit) for the state transition of the encoder at the reciver side while > at the trasnmitter side we only generated two 1-bit (total 2 bit)outputs > for state transition... > > third question..how do we calculate metric for soft decision.....and what > is soft-bit's impact on path metric and branch metric units of a viterbi > decoder.....This is interesting. If you look at a thread with title 'qpsk viterbi decoding', the poster is asking exactly the same question. Do you guys happen to be working for the same company, competing companies, or the same design project? ;-) Hope that helps, Julius

Reply by ●March 22, 20072007-03-22

On Mar 22, 5:08 pm, "julius" <juli...@gmail.com> wrote:> On Mar 22, 6:18 am, "khurram712" <khurram...@hotmail.com> wrote: > > > > > hello everyone... > > > my questions are related to k=7 rate=1/2 decoder and i am thinking of > > implementing it on FPGA using VHDL.....a general solution will also be > > appreciated. > > > first question..for 3 bit soft-decision coding is it the encoder that > > encodes 1 input to 2 3-bit encoded outputs or is it the reciever before > > viterbi decoder that quantizes the recieved encoded value to 2 3-bit > > encoded values.....i think it is the reciever...what do you say... > > > second question....if the answer to the first question is reciever then > > for soft bit decision how do we generate a two 3-bit expected value(total > > six bit) for the state transition of the encoder at the reciver side while > > at the trasnmitter side we only generated two 1-bit (total 2 bit)outputs > > for state transition... > > > third question..how do we calculate metric for soft decision.....and what > > is soft-bit's impact on path metric and branch metric units of a viterbi > > decoder..... > > This is interesting. If you look at a thread > with title 'qpsk viterbi decoding', the poster > is asking exactly the same question. > > Do you guys happen to be working for the same > company, competing companies, or the same design > project? ;-) > > Hope that helps, > JuliusNevermind, I should have thought that some people like to start multiple threads on basically the same question. Julius

Reply by ●March 22, 20072007-03-22

julius wrote: ...> Nevermind, I should have thought that some people > like to start multiple threads on basically the > same question.That's a very stupid thing to do because it means that answers to the question will be in different places without cross fertilization. Asking twice is an example of a stupid question. Stupid questions do exist! :-) Jerry -- Engineering is the art of making what you want from things you can get. ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

Reply by ●March 23, 20072007-03-23

julius wrote:> On Mar 22, 6:18 am, "khurram712" <khurram...@hotmail.com> wrote: >> hello everyone... >> >> my questions are related to k=7 rate=1/2 decoder and i am thinking of >> implementing it on FPGA using VHDL.....a general solution will also be >> appreciated. >> >> first question..for 3 bit soft-decision coding is it the encoder that >> encodes 1 input to 2 3-bit encoded outputs or is it the reciever before >> viterbi decoder that quantizes the recieved encoded value to 2 3-bit >> encoded values.....i think it is the reciever...what do you say... >> >> second question....if the answer to the first question is reciever then >> for soft bit decision how do we generate a two 3-bit expected value(total >> six bit) for the state transition of the encoder at the reciver side while >> at the trasnmitter side we only generated two 1-bit (total 2 bit)outputs >> for state transition... >> >> third question..how do we calculate metric for soft decision.....and what >> is soft-bit's impact on path metric and branch metric units of a viterbi >> decoder..... > > > This is interesting. If you look at a thread > with title 'qpsk viterbi decoding', the poster > is asking exactly the same question. > > Do you guys happen to be working for the same > company, competing companies, or the same design > project? ;-)Sitting in the same lecture theatre? :-) Steve

Reply by ●March 26, 20072007-03-26

>julius wrote: >> On Mar 22, 6:18 am, "khurram712" <khurram...@hotmail.com> wrote: >>> hello everyone... >>> >>> my questions are related to k=7 rate=1/2 decoder and i am thinking of >>> implementing it on FPGA using VHDL.....a general solution will alsobe>>> appreciated. >>> >>> first question..for 3 bit soft-decision coding is it the encoder that >>> encodes 1 input to 2 3-bit encoded outputs or is it the recieverbefore>>> viterbi decoder that quantizes the recieved encoded value to 2 3-bit >>> encoded values.....i think it is the reciever...what do you say... >>> >>> second question....if the answer to the first question is recieverthen>>> for soft bit decision how do we generate a two 3-bit expectedvalue(total>>> six bit) for the state transition of the encoder at the reciver sidewhile>>> at the trasnmitter side we only generated two 1-bit (total 2bit)outputs>>> for state transition... >>> >>> third question..how do we calculate metric for soft decision.....andwhat>>> is soft-bit's impact on path metric and branch metric units of aviterbi>>> decoder..... >> >> >> This is interesting. If you look at a thread >> with title 'qpsk viterbi decoding', the poster >> is asking exactly the same question. >> >> Do you guys happen to be working for the same >> company, competing companies, or the same design >> project? ;-) > >Sitting in the same lecture theatre? :-) > >Steve >hello everyone i posted the two questions but... the questions were different....the qpsk viterbi was related to slicer and node synchronization.... and the softbit metric was related to euclidean distance... i cant understand how you can see both questions to be the same...anyway please send some answers....