| 摘要 |
A prepit detection unit for detecting prepits in an optical recording and reproducing apparatus for recording and reproducing information on a recordable, optical record medium including preinformation such as address information in a prepit form. In the prepit detection unit, for first and second divisional RF signals output from a pickup being divided into a first divisional light reception part and a second divisional light reception part by a division line optically parallel to the tangential direction of an information track for receiving reflected light from the optical record medium, mark sections and space sections are clamped by potential correction circuits and a difference is found by a radial push-pull circuit.
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