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:
Jan. 11, 1983
Filed:
Jan. 21, 1981
Toshihito Ichikawa, Kawagoe, JP;
Pioneer Electronic Corporation, Tokyo, JP;
Abstract
An AM stereophonic receiver in which degradation of the quality of reproduced sound due to a decreased electric field strength is prevented. A main signal detector produces a sum signal representing the sum of first and second channel signals while a sub signal detector produces a difference signal representing the difference therebetween. The sum signal is coupled directly to a matrix circuit while the difference signal is coupled through a variable control type low-pass filter and a monophonic/stereophonic switch to the matrix circuit. The low-pass filter is controlled by a detection signal representative of the electric field strength of the received signal to reduce high frequency components when the electric field strength decreases below a predetermined value. The low-pass filter is bypassed when the electric field strength is sufficiently high.