VITERBI DECODING

HI,

   I want to know about error correcting capability of a convolution code
i.e. how many errors can be corrected in a continuous input  data pattern
(e.g.  a 1/2 rate code with constraint length of 7 has free distance of 10
and is said to correct 4 errors, whether these errors cab be burst type
also and what will be the relation of this error correction to input
data)?

 Thanks

On Thu, 31 Dec 2009 08:58:07 -0600, fsm12 wrote:

> HI,
> 
>    I want to know about error correcting capability of a convolution
>    code
> i.e. how many errors can be corrected in a continuous input  data
> pattern (e.g.  a 1/2 rate code with constraint length of 7 has free
> distance of 10 and is said to correct 4 errors, whether these errors cab
> be burst type also and what will be the relation of this error
> correction to input data)?
> 
>  Thanks

Your question isn't clear.  Viterbi decoders (or any other decoders, for 
convolutional or block codes) have a maximum-length burst that they can 
correct for (I think that's your "4 errors"), and in general an error 
rate that they can correct for.

Given a long enough burst, any decoder will fall down on the job.  Most 
practical channels tend to suffer from burst errors, so most practical 
FEC schemes -- convolutional or block -- reorder the encoded data.  Then 
when the data is put back into the correct order at the receiver a burst 
error is turned into a bunch of individual bit errors which are easier 
for the decoder to deal with.

-- 
www.wescottdesign.com

fsm12 wrote:

> HI,
> 
>    I want to know about error correcting capability of a convolution code
> i.e. how many errors can be corrected in a continuous input  data pattern
> (e.g.  a 1/2 rate code with constraint length of 7 has free distance of 10
> and is said to correct 4 errors, whether these errors cab be burst type
> also and what will be the relation of this error correction to input
> data)?

D = 2t + 1


VLV