RECORDING/REPRODUCTION DEVICE, EVALUATION VALUE CALCULATION METHOD, AND EVALUATION VALUE CALCULATION DEVICE

摘要

It is possible to obtain an appropriate evaluation value for setting a recording condition by using a simple configuration in a recording/reproduction system for performing PRML decoding. The signal quality evaluation value dSAM is a value equivalent to the difference between: a difference metric between the most likelihood path for an equalization signal supplied to a most likelihood decoding process and the path of the bit advance shift direction; and a difference metric between the most likelihood path for the equalization signal and the path of the bit delay shift direction. Moreover, the signal quality evaluation value dSAM is calculated by using an equalization error value ek as a difference between the equalization signal value supplied to the most likelihood decoding process and an ideal equalization signal value calculated from the decoded signal obtained as the result of the most likelihood decoding process.