Limbach & Limbach
Asymmetry detector for use in an optical recording and reproducing device
 This invention relates to an optical disc apparatus and the evaluating method of the optical disc apparatus, which emits the light beam to the disc typed recording medium to sequentially form pits and records the desired data, and the asymmetry, etc. can be detected rapidly and surely. The peak value and the bottom value of the reproduced signal are sequentially held to detect the minimum value and the maximum value of the held result, and then the recording system, the characteristics of the disc typed recording medium, or the reproducing system can be evaluated based on the detected result. 
Sony Corporation
G
G11B
inventional
Shinji Hiroyuki
Ohta Ito