Optical disk device

An optical disk device comprising:

• a first photodetector for detecting a light signal which is divided into four parts by a track direction axis and a radial direction axis that is perpendicular to the track direction axis, from an optical recording medium on which address information exists intermittently in an embossed area or an optical recording medium on which a burst;
• cutting area wherein information of the medium is described exists;
• an optical difference signal detection circuit for adding, among the outputs of the first photodetector which have been current-to-voltage converted, the outputs corresponding to areas parallel to the track direction axis, and detecting a difference between the respective added values;
• an amplitude adjustment circuit for adjusting the amplitude of an output signal of the optical difference signal detection circuit;
• a clock generation circuit for generating, from the output signal of the optical difference signal detection circuit, a sampling clock having a frequency that is synchronized with digital data recorded on the optical recording medium;
• a first analog-to-digital converter for converting an output signal of the amplitude adjustment circuit into a digital sampling signal according to the sampling clock;
• a second photodetector for detecting a focus error signal;
• a reproduction signal detection circuit for detecting a reproduction RF (Radio Frequency) signal using, among the outputs from the first photodetector which have been current-to-voltage converted, the outputs corresponding to the areas parallel to the track direction axis which have been added, and the output from the second photodetector which has been current-to-voltage converted;
• a reproduction signal amplitude adjustment circuit for performing amplitude adjustment of the output signal from the reproduction signal detection circuit;
• an equalizer for emphasizing a high-pass component of the output signal from the reproduction signal amplitude adjustment circuit;
• a second analog-to-digital converter for converting the output signal of the equalizer into a digital RF signal according to the sampling clock generated from the clock generation circuit;
• a reproduction signal selection circuit for selecting one of the digital sampling signal outputted from the first analog-to-digital converter and the digital RF signal;
• an address polarity information detection circuit for detecting a peak envelope signal from the output signal of the reproduction signal selection circuit, and comparing the peak envelope signal with a predetermined threshold value, thereby detecting address polarity information, or BCA (Burst Cutting Area) information recorded in the burst cutting area;
• and
• an address position information detection circuit for detecting a bottom envelope signal from the output signal of the reproduction signal selection circuit, detecting signal amplitude information from a difference in amplitudes between the peak envelope signal and the bottom envelope signal, and comparing the signal amplitude information with a predetermined threshold value, thereby detecting address position information.