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Viterbi Decoder

Started by fsm12 January 1, 2010

 I want to know that for a particular viterbi  decoder e.g for 1/2,7 type
,with traceback depth of 48, if input data frame contains 2000 bits ,IS it
possible to correct only upto 4 errors in this data stream and is there any
relation between error correcting capability and location of these errors
in the data pattern?


fsm12 wrote:
> I want to know that for a particular viterbi decoder e.g for 1/2,7 type > ,with traceback depth of 48, if input data frame contains 2000 bits ,IS it > possible to correct only upto 4 errors in this data stream and is there any > relation between error correcting capability and location of these errors > in the data pattern?
D >= 2t + 1 STUPIDENT
On Fri, 01 Jan 2010 01:10:15 -0600, fsm12 wrote:

> I want to know that for a particular viterbi decoder e.g for 1/2,7 type > ,with traceback depth of 48, if input data frame contains 2000 bits ,IS > it possible to correct only upto 4 errors in this data stream and is > there any relation between error correcting capability and location of > these errors in the data pattern?
OK, think. "Can I only correct four errors ever, no matter how long my data stream is". If yes, why would Viterbi decoders be so popular? Yes, it's a thing of mathematical beauty, but engineers are paid because we help our clients make money. So, the answer must be no, because if it were yes then the cell phone companies (which use pretty good protocols, all in all) wouldn't touch it with a ten foot pole (or, for that matter, a ten foot russian). In particular, a Viterbi decoder can massively reduce the error _rate_ in a stream that has a given error _rate_ -- there will always be clusters of errors that the Viterbi decoder cannot fix, but as the incoming error rate goes down the outgoing error rate goes down way, way faster. Why don't you experiment with a Viterbi decoder for a bit, and see for yourself how this is true? -- www.wescottdesign.com
> > > I want to know that for a particular viterbi decoder e.g for 1/2,7
type
>,with traceback depth of 48, if input data frame contains 2000 bits ,IS
it
>possible to correct only upto 4 errors in this data stream and is there
any
>relation between error correcting capability and location of these
errors
>in the data pattern? > >
This does not answer my query at all> Is it not possible to Quantify the values of errors corrected by a Viterbi decoder for a given input data stream (e.g. for a 2000 inputs bits fed to a decoder having free distance of 10.)
On 1/2/2010 8:19 AM, fsm12 wrote:
>> >> I want to know that for a particular viterbi decoder e.g for 1/2,7 > type >> ,with traceback depth of 48, if input data frame contains 2000 bits ,IS > it >> possible to correct only upto 4 errors in this data stream and is there > any >> relation between error correcting capability and location of these > errors >> in the data pattern? >> >> > > This does not answer my query at all> Is it not possible to Quantify the > values of errors corrected by a Viterbi decoder for a given input data > stream > (e.g. for a 2000 inputs bits fed to a decoder having free distance of > 10.)
Unlike algebraic codes, convolutional codes are more sensitive to input error distribution. Clumps of errors, especially as the clump lengths compare to the constraint length, are far harder to correct with a convolutional code than an algebraic code. So, no, it is not possible to strictly say that a CC can correct N out of M bits, because the distribution of the errors matters. Randomly distributed errors are easier to correct than clumps. This is why channel interleavers are sometimes used. -- Eric Jacobsen Minister of Algorithms Abineau Communications http://www.abineau.com

fsm12 wrote:
>> >>I want to know that for a particular viterbi decoder e.g for 1/2,7 > > type > >>,with traceback depth of 48, if input data frame contains 2000 bits ,IS > > it > >>possible to correct only upto 4 errors in this data stream and is there > > any > >>relation between error correcting capability and location of these > > errors > >>in the data pattern? >> >> > > > This does not answer my query at all> Is it not possible to Quantify the > values of errors corrected by a Viterbi decoder for a given input data > stream > (e.g. for a 2000 inputs bits fed to a decoder having free distance of > 10.)
Yes, it is possible to quantify this. The cost of this homework question is $500. VLV
>> >> >> I want to know that for a particular viterbi decoder e.g for 1/2,7 >type >>,with traceback depth of 48, if input data frame contains 2000 bits ,IS >it >>possible to correct only upto 4 errors in this data stream and is there >any >>relation between error correcting capability and location of these >errors >>in the data pattern? >> >> > > This does not answer my query at all> Is it not possible to Quantify
the
>values of errors corrected by a Viterbi decoder for a given input data >stream >(e.g. for a 2000 inputs bits fed to a decoder having free distance of >10.) > >
Dude, that is ~15 lines of Matlab code to experiment with coding rates, block lengths, polynomials, interleaver types, etc.
On Jan 2, 6:26=A0pm, "rbb" <Rory.Bucha...@onsemi.com> wrote:
> >> I want to know that for a particular viterbi =A0decoder e.g for 1/2,7 > >type > >>,with traceback depth of 48, if input data frame contains 2000 bits ,IS > >it > >>possible to correct only upto 4 errors in this data stream and is there > >any > >>relation between error correcting capability and location of these > >errors > >>in the data pattern? > > > This does not answer my query at all> Is it not possible to Quantify > the > >values of errors corrected by a Viterbi decoder for a given input data > >stream > >(e.g. for a 2000 inputs bits fed to a decoder having free distance of > >10.) > > Dude, that is ~15 lines of Matlab code to experiment with coding rates, > block lengths, polynomials, interleaver types, etc. =A0
Have you checked the price of Matlab and toolboxes lately? Have you checked if the m-files needed to do this are available in Octave?
>On Jan 2, 6:26=A0pm, "rbb" <Rory.Bucha...@onsemi.com> wrote: >> >> I want to know that for a particular viterbi =A0decoder e.g for
1/2,7
>> >type >> >>,with traceback depth of 48, if input data frame contains 2000 bits
,IS
>> >it >> >>possible to correct only upto 4 errors in this data stream and is
there
>> >any >> >>relation between error correcting capability and location of these >> >errors >> >>in the data pattern? >> >> > This does not answer my query at all> Is it not possible to Quantify >> the >> >values of errors corrected by a Viterbi decoder for a given input
data
>> >stream >> >(e.g. for a 2000 inputs bits fed to a decoder having free distance of >> >10.) >> >> Dude, that is ~15 lines of Matlab code to experiment with coding
rates,
>> block lengths, polynomials, interleaver types, etc. =A0 > >Have you checked the price of Matlab and toolboxes lately? Have you >checked if the m-files needed to do this are available in Octave? >
Well it would take a bit more time, but you could easily do everything I said in your favorite programming language. C/C++/C#/VB/etc.