OPTICAL INFORMATION RECORDING AND PLAYBACK DEVICE AND RECORDING MARK QUALITY MEASURING METHOD

摘要

An equalizer (22) carries out a PR equalization of a playback signal waveform output by an AD converter (21). A reference waveform generator (42) generates a reference playback waveform in accordance with a recorded data sequence estimated from the playback signal waveform by an identifier (30). An equalized error calculator (43) calculates an equalized error between the reference playback waveform and the playback signal waveform. A transient time equalized error detector (44) extracts equalized error information as a transient time equalized error at the time when the reference playback waveform has a predetermined value and, further, when such a predetermined value and a reference playback waveform level value at one channel clock ahead or behind satisfy a predetermined relative relationship. The extracted transient equalized error is used as an index to express the defined quality of a recorded mark.