| 摘要 |
An information record employs a storage medium comprising a metallized base material having a dielectric coating thereon. The dimensions of an information track contained in a groove in the storage medium vary in accordance with recorded information pursuant to an information-representative pattern of relatively raised and depressed areas, the former constituting undisturbed regions of the groove bottom. The information track may comprise (1) an AM carrier pattern wherein a carrier frequency amplitude modulated by the video signals is represented by successive pairs of regions, a first region of each pair having the relative widths of a central depressed area and adjoining raised areas determined by video signal amplitude, and the succeeding region of each pair having the relative widths of a central raised area and adjoining depressed areas complementarily determined; or (2) a FM carrier pattern, wherein depressed areas extending across the width of the groove bottom alternate with raised areas extending across the width of the groove bottom, and the spacing between successive areas of the same type varies with video signal amplitude. The capacitance between an electrode in a pickup tracking in said groove and the metallized surface of the storage medium varies in accordance with the modulated information track as the pickup device scans the recording medium. Circuitry responding to said capacitance variations provides an output signal corresponding to the information recorded. One application of such a system is to record, on both sides of a disc, video information which can be reproduced in form of a video display. |
