SIGNAL QUALITY EVALUATION DEVICE AND METHOD, AND INFORMATION RECORDING/REPRODUCING DEVICE

摘要

A level average value calculator generates a reference value for branch metric calculation by a Viterbi detector by using a detected data string outputted by the Viterbi detector and the output of an equalizer. An error vector calculator obtains the difference between the reference values with respect to the paths for a pair of signal strings which may easily cause an error mutually and generates an error vector whose component is the value based on the difference between the reference values. An effective noise calculator obtains an inner product of the error vector and the vector whose element is the time-series data on a Viterbi error obtained by a Viterbi error calculator and calculates a square mean value of the inner product. An evaluation index calculator calculates a signal quality evaluation value from the size of the error vector and the square mean value of the inner product calculated by the effective noise calculator.