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. 26, 2004
Filed:
Jun. 10, 2003
Naomi Ohashi, Yokohama, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
An AGC circuit suitable for applications such as an optical receiving apparatus includes a differential amplification adjustment circuit section for operating on a pair of input signals to produce a corresponding pair of complementary controlled output signals having a fixed amplitude, a peak detector for detecting a peak value of at least one of the controlled output signals, a DC monitoring circuit for detecting the DC level of at least one of the controlled output signals, and an amplitude fixing control circuit for deriving a value of voltage difference between the peak value and DC level and for generating an amplitude control signal based on comparing the voltage difference with a reference voltage. The differential amplification adjustment circuit section applies a degree of amplification that is determined by the amplitude control signal, to thereby perform feedback control of the output signal amplitude. The AGC circuit can further be configured to control the DC levels of the controlled output signals, so that both DC level and amplitude of the controlled output signals are held constant against changes in DC level and amplitude of the input signals.