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. 19, 1991
Filed:
Dec. 22, 1989
Thomas L Field, Rutland, MA (US);
Oliver L Richards, Jr, N. Grosvenor Dale, CT (US);
Sprague Electric Company, North Adams, MA (US);
Abstract
A stereo FM radio transmission system with FMX transmission and reception capability includes a transmitter that transmits a pilot-coherent FMX-tone indicator signal at a frequency of an exact integer submultiple of the pilot frequency. The system also includes a receiver for dividing the frequency of the received pilot signal by various submultiples, nearly equal to the exact submultiple, toward quickly finding a match in phase of the received tone and the received pilot and finally dividing the pilot by the exact submultiple to establish an operational lock mode of the receiver tone detector to keep-on an FMX-indicator lamp, to change the receiver decoder to an FMX-reception operating mode and to stand by to quickly recapture the pilot and FMX-tone in the event of multipath or other interfering signals.