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:
Oct. 07, 1997
Filed:
Dec. 05, 1995
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
A recorded signal reproduction circuit in an optical disc information reading and recording apparatus converts a recorded signal recovered from an optical disc to PR (1, 2, 1) characteristics through a equalizer circuit, digitizes it through an A/D converter and at the same time also generates a clock signal synchronized in phase with the equalizer circuit output signal by using a binary edcoder circuit and a PLL circuit. This clock signal is then provided to an A/D converter as the sampling clock. The A/D converter output signal is then decoded to the original channel bit stream based on the clock signal. Because the equalizer circuit output signal is provided to both the binary encoder/PLL circuit and the A/D converter together, additional circuity for converting signals into a binary series of pulses is unnecessary and reduction of circuit scale is possible. Moreover, in case of a change-over in the frequency characteristics of the equalizer circuit, due to a change in recording and reproduction frequency, the change-over will not affect the phase relationship between an input signal to the A/D converter and a sampling clock. In addition, it becomes simple to adjust this phase relation.