Abstract: Recovery from a record of data recorded in an elongated information track, comprising undulations representative of the data is effected by an optical playback system. In the system, the data is recorded within two substantially different frequency bands. The optical playback system has a dual response characteristic to provide improved response at the two different frequency bands. A modifying means interposed in the light beam path shapes the light beam to effect this dual response characteristic (i.e., two different bandwidth responses).

Abstract: An apparatus for tracking, by means of radiating beams of light, a record disc (6) which contains video or audio signals recorded in optical form. First and second lasers (1a, 1b) generate a first beam for reading out recorded information, and a second beam for tracking, respectively. The first beam provides a first optical spot (8a) on an information track (7) and the second beam provides a second optical spot (8b) in close proximity to the first spot. The first and second beams are selected alternately. The reflected second beam is detected by a radiation-sensitive detector (20) and compared with a reference signal level. The position of the optical system (200), including the first and second lasers, is physically adjusted by shifting means (14) in response to amplitude differences between the detected signal caused by the second beam and the reference signal level to implement accurate tracking control in spite of spindle hole eccentricities or the like.