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:
May. 26, 2009
Filed:
Aug. 18, 2004
Applicants:
Shigekiyo Fujii, Kanagawa, JP;
Hiroshi Kondo, Kanagawa, JP;
Yoshiyuki Yoshizumi, Kanagawa, JP;
Inventors:
Assignee:
Panasonic Corporation, Osaka, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04R 25/00 (2006.01); H03G 3/00 (2006.01);
U.S. Cl.
CPC ...
Abstract
A technique is disclosed, which can shorten attack time and release time without using RC filter with time constant. According to this technique, diodesandrectify AC signal at output stage of an amplifierby voltage doubler rectification, and a smoothing capacitorsmoothens the signals rectified by the diodesand. A transistorof an attenuation circuitturns on when DC voltage smoothened by the smoothing capacitor exceeds a predetermined level, and level of the output signal of the amplifier is attenuated by drawing the input signal of the amplifier.