Kinji Kayanuma

High track density magneto-optical recording using a crosstalk canceler

High track density magneto-optical recording, using a crosstalk canceller which eliminates crosstalk from two adjacent tracks, has been developed. By this recording method, both land area and groove area can be used for data storage tracks, and twice the track density, cornpared with the conventional method, has been achieved. Applying this crosstalk canceller also realizes intersymbol interference compensation.

Multi-Beam Optical Disk Drive for High Data Transfer Rate Systems

A multi-beam optical disk drive, which improves the data transfer rate for magneto-optical disk systems, has been developed. The optical head employs an image rotator for tracing several tracks simultaneously. Four-channel parallel read/write operation has been achieved, and a digital video recording system with a data transfer rate of 22 Mbps has been realized. Real-time data verification at a linear velocity of 33 m/s has been demonstrated. Double track density recording, using a crosstalk canceler, has also been accomplished, and a 5.1×10-5 bit error rate has been obtained.

High-Density Land/Groove Recording for Digital Video File System

High-density land/groove recording technology for magnetooptical (MO) disks, using a high-speed crosstalk canceller which eliminates crosstalk from adjacent tracks, has been developed. A 0.50 µm/bit linear density with a 0.8 µm track pitch has been confirmed with a bit error rate (BER) less than 10-5. A digital video file system using this technology has also been developed. As a result, the authors confirmed the validity for the high-density land/groove recording technology in realizing larger capacity for digital video file systems.

High-density land/groove recording using PRML technology

High density land/groove recording, using partial response maximum likelihood (PRML) technology, which corrects errors in the readout signal for exploiting readout channel characteristics, has been developed. By this detection method, both land area and groove area can be used for data storage tracks without a crosstalk cancellation technique. Applying this method with a red laser, 8 times the storage capacity, compared with the conventional method, has been achieved.