Patent ID: 6292449
Filing Date: 2001-09-18
Classification: G11B

Abstract:
An optical disk apparatus comprising:a first head capable of moving in the radial direction of an optical disk;a second head which can be moved in the radial direction of the optical disk independently from said first head and which performs at least reproduction for the optical disk;a disk-rotating mechanism for rotating the optical disk at a constant linear velocity with respect to said first head;a time-axis expansion and compression adjuster for expanding and compressing the time axis of a signal read by said second head, according to the track position of said second head such that the time axis matches that obtained at a constant linear velocity; anda time-axis expansion and compression memory provided in said time-axis expansion and compression adjuster that temporarily stores therein a signal read by said second head in order to expand or compress the pulse width of the signal read by said second head correspondingly to the time axis obtained at a constant linear velocity, whereinwhen second head is positioned radially inside of said first head, said second head is controlled so as to jump a track according to the track position of said second head, and the pulse width of a signal read by said second head is compressed with the use of the time-axis expansion and compression memory such that the time axis of the signal read by said second head matches that obtained at a constant linear velocity, andwhen second head is positioned radially outside of said first head, said second head is temporarily stopped according to the track position of said second head, and the pulse width of a signal read by said second head is expanded with the use of the time-axis expansion and compression memory such that the time axis of the signal read by said second head matches that obtained at a constant linear velocity.