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:
Mar. 21, 2006
Filed:
Jul. 27, 2004
Takuma Ishida, Osaka, JP;
Keiichi Fujii, Shiga, JP;
Takuma Ishida, Osaka, JP;
Keiichi Fujii, Shiga, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
An AGC circuit of the present invention includes a first up/down counter for converting the amount of change in an output voltage higher than a threshold voltage into a count value and controlling a gain of a variable gain amplifier circuit and a second up/down counter to which a reference clock having a lower frequency than that of a reference clock supplied to the first up/down counter is supplied. Count values of the first and second up/down counters are D/A-converted and then compared with each other by a voltage comparator. An up/down count of the first up/down counter is controlled based on a comparison result and the gain of the variable gain amplifier circuit is controlled using only a signal based on the count value of the first up/down counter, thereby suppressing distortion of an output waveform and the generation of a frequency signal which is not originally input.