High density recording for magneto-optical disk drive

To obtain key technique for 1.9 Gbit/in/sup 2/ magneto-optical recording, a new wide groove recording structure and a new edge shift detection method are investigated. Track pitch of 0.85 /spl mu/m is accomplished by the wide groove recording structure. The structure improves signal-to-noise ratio up to +6.5 dB. Recording and playback conditions are precisely controlled with the use of the new edge shift detection method. The detection method separately detects mark edge shifts and inter-symbol interferences by analyzing edge shifts in playback signal. Maximum edge shift of 3% to (1,7) detecting window at bit pitch of 0.40 /spl mu/m is achieved.