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:
Apr. 13, 1993
Filed:
Dec. 27, 1990
Motoshi Ito, Toyonaka, JP;
Kenzo Ishibashi, Moriguchi, JP;
Takashi Inoue, Osaka, JP;
Shunji O'Hara, Higashiosaka, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
Data read from an optical disk includes an address period, an ALPC period and a data period, in which the ALPC period contains a no-signal state at opposite ends of a laser output signal. An ALPC period detector is provided for detecting the ALPC period. During the ALPC period, an automatic gain control circuit is suspended to hold the gain to the predetermined value. Alternatively, during the ALPC period, the signal applied to the automatic gain control circuit is reduced to ground level or is attenuated. Thus, since the automatic gain control circuit will not be adversely affected by the laser output signal and no-signal state in the ALPC period, the automatic gain control circuit will amplify the signal in the data period with an appropriate gain.