| 摘要 |
A grooveless record having parallel tracks on which information is recorded as a series of microscopic pits is illuminated with a laser which reflects off to a pair of first and second adjoining optoelectrical sensing elements (7a, 7b) to generate respective output signals so that the sensing elements are equally illuminated when the laser beam is kept at a predetermined angle of incidence on the path of the record track. To compensate for tracking errors resulting from the tilting of the record, there is derived from the sensing elements a pair of first and second peak value signals each bearing exclusively the information on the tilt angle. The output signals from the first and second sensing elements are modulated in magnitude with the first and second peak value signals by multiplier circuits (30, 31; 40, 41) and fed to a subtractor (37; 70) for detecting the difference between the two modulated signals to generate a tracking control signal so that the error information is nullified at the output of the subtractor.
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