Maximum likelihood sequence metric calculator

Claim 1

An apparatus for a maximum likelihood sequence metric calculator used in decoding sampled values from a communication channel or recording device comprising: a first adding means having as inputs a sampled input signal and the negative of a threshold voltage; a first peak detecting means coupled to said first adding means providing a first output signal; a first comparing means coupled to said first adding means and said first peak detecting means for providing a second output signal; a first inverting means coupled to said first peak detector for providing a third output signal; a first resetting means coupled to said first inverting means and said first comparing means for providing a reset signal output; a second inverting means coupled to said sampled input signal; a second adding means coupled to said second inverting means and also coupled to the said negative of the threshold value; a second peak detecting means coupled to said second adding means and said first resetting means for providing a fourth output signal; a second comparing means coupled to said second adding means and to said second peak detecting means for providing a fifth output signal; a third inverting means coupled to said second peak detecting means for providing a sixth output signal; a second resetting means coupled to said third inverting means and to said second comparing means for providing a reset output signal to said first peak detecting means.

Claim 2

An apparatus for a maximum likelihood sequence metric calculator used in decoding sampled values from a communication channel or recording device comprising: a first adding means having as inputs a sampled input signal and the negative of a threshold voltage; a first peak detecting means coupled to said first adding means providing a first output signal; a first comparing means coupled to said first adding means and said first peak detecting means for providing a second output signal; a first inverting means coupled to said first peak detector for providing a third output signal; a first resetting means coupled to said first inverting means and said first comparing means for providing a reset signal output; a second inverting means coupled to said sampled input signal; a second adding means coupled to said second inverting means and also coupled to the said negative of the threshold value; a second peak detecting means coupled to said second adding means and said first resetting means for providing a fourth output signal; a second comparing means coupled to said second adding means and to said second peak detecting means for providing a fifth output signal; a third inverting means coupled to said second peak detecting means for providing a sixth output signal; a second resetting means coupled to said third inverting means and to said second comparing means for providing a reset output signal to said first peak detecting means.

Claim 4

An apparatus for a maximum likelihood sequence metric calculator used in decoding samples values from a communication channel or recording device comprising: a first peak detecting means receiving a sampled input signal for providing a first output signal; a first comparing means coupled to said sampled input signal and also coupled to said first peak detecting means for providing a second output signal; a first adding means coupled to said first peak detecting means and also coupled to the negative of twice a threshold voltage signal; a first inverting means coupled to said first adding means for providing a third output signal; a first resetting means coupled to said first inverting means and also coupled to said first comparing means for providing a reset output signal; a second inverting means coupled to said sampled input signal; a second peak detecting means coupled to said second inverting means and also coupled to said first resetting means for providing a fourth output signal; a second comparing means coupled to said second inverting means and also coupled to said second peak detecting means for providing a fifth output signal; a second adding means coupled to said second peak detecting means and also coupled to the negative of twice the threshold voltage signal; a third inverting means coupled to said adding means for providing a sixth output signal; a second resetting means coupled to said third inverting means and to said second comparing means for providing a reset output signal to said first peak detecting means.

Claim 5

An apparatus for a maximum likelihood sequence metric calculator used in decoding samples values from a communication channel or recording device comprising: a first peak detecting means receiving a sampled input signal for providing a first output signal; a first comparing means coupled to said sampled input signal and also coupled to said first peak detecting means for providing a second output signal; a first adding means coupled to said first peak detecting means and also coupled to the negative of twice a threshold voltage signal; a first inverting means coupled to said first adding means for providing a third output signal; a first resetting means coupled to said first inverting means and also coupled to said first comparing means for providing a reset output signal; a second inverting means coupled to said sampled input signal; a second peak detecting means coupled to said second inverting means and also coupled to said first resetting means for providing a fourth output signal; a second comparing means coupled to said second inverting means and also coupled to said second peak detecting means for providing a fifth output signal; a second adding means coupled to said second peak detecting means and also coupled to the negative of twice the threshold voltage signal; a third inverting means coupled to said adding means for providing a sixth output signal; a second resetting means coupled to said third inverting means and to said second comparing means for providing a reset output signal to said first peak detecting means.

Claim 8

An apparatus for maximum-likelihood sequence decoding of sample sequences with intersymbol interference from a communication channel or recording device comprising: a first peak detecting means for comparing and storing the largest amplitude positive pulse received from said sampled sequence; a first resetting means coupled to said first peak detecting means for resetting voltage value stored in said first peak detecting means after a negative transition pulse has been received; a first comparing means coupled to an input and an output of said first peak detecting means and providing a first flag signal indicating whether a larger positive peak has been detected; a second peak detecting means for comparing and storing the largest amplitude negative pulse received from said sampled sequence; a second resetting means coupled to said second peak detecting means and receiving said first flag signal for resetting voltage value stored in said second peak detecting means; a second comparing means coupled to an input and an output of said second peak detecting means and an output of said second comparing means being coupled to said first resetting means for providing a second flag signal to said first resetting means indicating whether a larger negative peak has been detected; a survivor sequence register scheme receiving said first and second flag signals for providing the maximum-likelihood sequence.

Claim 9

An apparatus for maximum-likelihood sequence decoding of sample sequences with intersymbol interference from a communication channel or recording device comprising: a first peak detecting means for comparing and storing the largest amplitude positive pulse received from said sampled sequence; a first resetting means coupled to said first peak detecting means for resetting voltage value stored in said first peak detecting means after a negative transition pulse has been received; a first comparing means coupled to an input and an output of said first peak detecting means and providing a first flag signal indicating whether a larger positive peak has been detected; a second peak detecting means for comparing and storing the largest amplitude negative pulse received from said sampled sequence; a second resetting means coupled to said second peak detecting means and receiving said first flag signal for resetting voltage value stored in said second peak detecting means; a second comparing means coupled to an input and an output of said second peak detecting means and an output of said second comparing means being coupled to said first resetting means for providing a second flag signal to said first resetting means indicating whether a larger negative peak has been detected; a survivor sequence register scheme receiving said first and second flag signals for providing the maximum-likelihood sequence.

Claim 11

A method of decoding a stream of received data having two states with intersymbol interference from a communication channel or recording device, the method comprising the steps of: computing a metric for each sample pulse received; comparing the most recent sampled positive or negative amplitude to previous stored sampled amplitude of same positive or negative amplitude; resetting an amplitude stored for the opposite polarity every time the latest peak of a plurality of consecutive peaks has a greater amplitude; generating flag signals during resetting operation to indicate a transition in state, said flag signals are stored and later corrected, if needed, to attain a most likely correct bit sequence corresponding to the decoded stream of data.

Claim 12

A method of decoding a stream of received data having two states with intersymbol interference from a communication channel or recording device, the method comprising the steps of: computing a metric for each sample pulse received; comparing the most recent sampled positive or negative amplitude to previous stored sampled amplitude of same positive or negative amplitude; resetting an amplitude stored for the opposite polarity every time the latest peak of a plurality of consecutive peaks has a greater amplitude; generating flag signals during resetting operation to indicate a transition in state, said flag signals are stored and later corrected, if needed, to attain a most likely correct bit sequence corresponding to the decoded stream of data.