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. 28, 1986
Filed:
Feb. 05, 1985
Toshiyuki Imagawa, Tokyo, JP;
Clarion Co., Ltd., Tokyo, JP;
Abstract
An automatic frequency control circuit is used in an FM stereo radio receiver which includes an intermediate frequency amplifying and detecting circuit producing an output for driving a signal meter and includes a multiplexer, so that the multiplexer effects controls to reduce noises in stereophonic and monophonic reception responsively to the signal meter driving circuit by changing its separation ratio and attenuation ratio. The circuit comprises: an adder which adds a dc voltage obtained by rectifying and smoothing ac components in the signal meter driving voltage to a dc voltage obtained by rectifying and smoothing noise components in an output from a noise cancellor; a comparator which compares the sum voltage from the adder with original dc components in the signal meter driving circuit; and a subtraction voltage generator which produces a subtraction voltage responsive to the difference between the compared two voltages, so that the noise reducing controls are effected responsively to the subtraction voltage.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile