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:
Apr. 01, 1986
Filed:
Mar. 26, 1984
Applicant:
Inventor:
Oliver L Richards, Jr, N. Grosvenor Dale, CT (US);
Assignee:
Sprague Electric Company, North Adams, MA (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H03J / ; H04B / ;
U.S. Cl.
CPC ...
455168 ; 455194 ; 455212 ; 455222 ; 455200 ;
Abstract
In an integrated AM-FM radio circuit connected for operation in the FM mode, the voltage appearing across the normally unused AM tank at the IF amplifier is noise in that AM band centered at 455 KHz. That noise, which is present only when the IF amplifier is not limiting due to the presence of an FM signal therein, is used for muting the receiver. The noise is passed through a simple IC-on-board low pass filter to a noise detector and then to a voltage controlled attenuator to attenuate the demodulated audio from the FM detector to the audio amplifier.