Super-Resolution Optical Readout System with Partial Response Maximum Likelihood Detection

概要

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A readout system that uses super-resolution optics and a partial response maximum likelihood (PRML) detection, which improves readout sensitivity and achieves high-density recording, has been developed. In this system, a shading band is placed in the collection path to shade the center part of the reflected beam across the track direction at the aperture plane, resulting in good optical transfer function (OTF) in the high-frequency region. The readout signal from the photo-detector is equalized for the partial responses channel using only a transversal filter and applying Viterbi detection. Experiments using a magneto-optical disk drive having a class I partial response (PR(1, 1)) and a run-length limited code (RLL(1, 7)) were performed to demonstrate the good readout sensitivity of this method. The results show that this compact system achieves 30% higher recording density than a conventional system.
Publication Office, Japanese Journal of Applied Physics, Faculty of Science, University of Tokyoの論文
1998-04-30