Sony Corporation

Mariko Fukuyama

Toshiki Shimizu

Jumpei Kura

Tadaaki Nomoto

An evaluation value calculating apparatus includes the following elements. A difference metric selecting unit selects a difference metric for a specific recorded sequence in recorded sequences obtained in a maximum likelihood decoding process when information expressed with marks and spaces on a recording medium is played back, the difference metric being obtained in the maximum likelihood decoding process. A difference metric error value calculating unit determines a difference metric error value for the selected difference metric using a calculation method that is selected according to an edge shift direction of each of the marks on a time axis, the difference metric error value representing an error from an ideal difference metric and the edge shift direction on the time axis. A statistical processing unit performs statistical processing on the determined difference metric error value on the basis of each of states of path meeting points to generate an evaluation value.

Evaluation value calculating apparatus, recording and playback apparatus, evaluation value calculating method, recording method

A demodulator for demodulating an input signal including a predetermined modulated signal includes a multiplication fundamental wave generator for outputting a multiplication fundamental wave for the predetermined modulated signal, a calculator for multiplying the multiplication fundamental wave by the input signal and for integrating the multiplication result, a demodulated signal generator for generating a demodulated signal of the modulated signal using the output from the calculator, a phase determiner for determining a cross-phase state of the input signal and the multiplication fundamental wave on the basis of a balance of levels of a plurality of integrated values, obtained as the integration result, for an interval containing the modulated signal in the input signal, and a phase adjuster for adjusting a phase of the multiplication fundamental wave to be supplied to the calculator on the basis of the determination result of the phase determiner.

Demodulator, disk drive device, and demodulation method

A data-decoding apparatus having bit-detecting section In the apparatus, an RF signal is reproduced from a recording medium and converted to digital data. If the RF signal has a level (amplitude) equal to a comparator level, the bit-detecting section outputs channel-bit data having logic level &ldquo;0&rdquo; or &ldquo;1&rdquo; in accordance with whether the sum of the amplitudes of the two RF signals respectively preceding and following that RF signal is higher or lower than the comparator level.

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Tokyo, Japan

Mariko Fukuyama