A Review of the MCA Disco-Vision System

Broadbent, Kent D.

doi:10.5594/j10631

Cited by 18 publications

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

A magnetooptic video disk readout method using a pair of polarized laser beams

Ishii

1980

Electron. Comm. Jpn. Pt. I

View full text Add to dashboard Cite

A new symbol readout method employing two readout laser beams that intersect at a specified angle on the magnetic medium surface and are orthogonally polarized with respect to each other is proposed. The diffracted light signal is detected in reproducing the FM video signal, that is, it is recorded thermomagnetically on a magnetic film as recording medium (e.g., a rotating disk memory) using magnetooptic effects. The effects of the readout frequency characteristic, and the readout beam defocus are analyzed. The diffracted light of the high‐frequency signal generated by the signal recording track overlaps the zero‐order diffracted light. By adjusting the intersecting angle of the readout laser beams in such a way that sufficient overlapped light is obtained, the higher‐frequency limit of the readout frequency characteristic can be emphasized. Further, in order to obtain flat FM demodulator characteristic, the needed readout frequency characteristic that attenuates linearly in the neighborhood of FM carrier frequency is realized easily by optical means. As a result of greater emphasis on the larger limit the signal‐to‐noise ratio is improved. It is possible to reduce the output of the readout laser light source to less than half, when compared to the conventional magnetooptic readout methods employing a single beam.

show abstract