The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 01, 1999
Filed:
May. 27, 1997
Hideyo Kamiyama, Tokorozawa, JP;
Pioneer Electronic Corporation, Tokyo, JP;
Abstract
A disk discrimination apparatus for use in an optical disk reproducing apparatus detects a tracking error signal, discriminates between disks, and prevents reproduction of a disk which does not correspond to the reproducing apparatus. In the disk discrimination apparatus, when a second type disk, having a track pitch which is smaller than that of a first type disk, is played by the optical disk reproducing apparatus, a discriminator detects that the disk is not a first type disk based on an output signal of a tracking error signal generating circuit. The discriminator performs a discrimination operation by comparing the signal level of a tracking error signal with a predetermined reference value. In another embodiment, the discriminator includes a counter for counting the number of zero-crossings of the tracking error signal, and performs the disk discrimination using a count value produced by the counter.