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.:

US 6989717 B1

PDF
Full Text
Expired
Date of Patent:
Jan. 24, 2006

Filed:

Dec. 03, 2002
Applicants:

Masamichi Nogami, Tokyo, JP;

Kuniaki Motoshima, Tokyo, JP;

Inventors:

Masamichi Nogami, Tokyo, JP;

Kuniaki Motoshima, Tokyo, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H03F 3/08 (2006.01);
U.S. Cl.
CPC ...
Abstract

A pre-amplifier amplifies an output current of a photodetector that converts a burst optical signal into an electrical signal, and outputs an electric voltage signal. A gain switching circuit is connected with a serial circuit comprising a resistor and a switch and a serial circuit comprising a resistor and a switch, in parallel with a feedback resistor. The gain switching circuit includes an arrangement to receive the electric voltage signal output from the pre-amplifier, close the switch at a specific bit position, close the switch at the other specific bit position, upon occurrence of a situation that the switch is to be closed, provided that the switch is closed.


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