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:
Sep. 24, 1996
Filed:
Aug. 29, 1994
Tomoyuki Hiroki, Zama, JP;
Hisatoshi Baba, Yokohama, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
In an automatic gain control device, an error signal generated based on output signals from a divided sensor is inputted to an operational amplifier. A sum signal of the output signals from the divided sensor is inputted to a multiplier. The error signal is divided by the sum signal by negatively feeding back an output signal from the operational amplifier to the operational amplifier via the multiplier. Two predetermined voltages are alternately applied to the multiplier in a state in which the sum signal is 0. The amplitudes of output signals from the automatic gain control device corresponding to the two voltages are detected. Input offsets of the operational amplifier and the multiplier are cancelled by calculating the input offsets of the operational amplifier and the multiplier on the basis of the detected amplitudes of the signals, the two predetermined voltages, and a gain of the multiplier.