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. 06, 1999
Filed:
May. 22, 1997
Eiji Saruwatari, Tokyo, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
An optical signal is converted by a light-receiving element into a photoelectric current. The photoelectric current is converted by a preamplifier into a positive phase voltage and the opposite phase voltage. The peaks of the positive phase output and opposite phase output are sensed and held by a first and second peak sensing circuits. The median between the output of the second peak sensing circuit and the positive phase output of the preamplifier is determined by a first median output circuit. The median between the output of the first peak sensing circuit and the opposite phase output of the preamplifier is determined by a second median output circuit. A level comparison circuit compares the outputs of the first and second median output circuits and produces a signal voltage with a constant amplitude within a specific input voltage range, thereby producing a reception signal. This helps alleviate duty fluctuations and the deterioration of the reception sensitivity resulting from the dark current of the light-receiving element or fluctuations in the output offset voltage of the preamplifier.