Patent ID: 7603591

Claim:
An apparatus for decoding an input signal to generate an output signal, the apparatus comprising: a noise detector for determining burst noise locations corresponding to the input signal and generating a first indication signal accordingly; an inner decoder for decoding the input signal to generate an inner-code decoded signal; a reliability-determining unit, coupled to the noise detector, for receiving the first indication signal generated from the noise detector, and selectively adopting one of a plurality of determining criteria according to the first indication signal to determine reliability information corresponding to the inner-code decoded signal and to generate a second indication signal accordingly; and an outer decoder, coupled to the inner decoder and the reliability-determining unit, for decoding the inner-code decoded signal with reference to the second indication signal to generate the output signal; wherein if the first indication signal is asserted by the noise detector, the reliability-determining unit adopts a first determining criterion to determine the reliability information corresponding to the inner-code decoded signal, and if the first indication signal is not asserted by the noise detector, the reliability-determining unit adopts a second determining criterion to determine the reliability information corresponding to the inner-code decoded signal; and wherein the inner decoder decodes the input signal according to a Viterbi algorithm, for a state having two candidate path metrics in the Viterbi algorithm, if the first determining criterion is adopted, the reliability-determining unit determines a reliability corresponding to the state through comparing a first threshold with a difference between the two candidate path metrics; and if the second determining criterion is adopted, the reliability-determining unit determines the reliability corresponding to the state through comparing a second threshold with the difference.