Method and system for signalling additional information by AM medium wave broadcasting
Patent 4679238 Issued on July 7, 1987. Estimated Expiration Date: 
April 25, 2005. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
April 25, 2005. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesIn-band signaling system for FM transmission systems Multiple tone signal system Process and a circuit arrangement for signal transmission using an amplitude-modulated radio broadcasting system Signaling system for FM transmission systems Patent #: 4534054 InventorsApplicationNo. 06/727371 filed on 04/25/1985US Classes:381/16, Having transmitter381/15AM or both AM and angle final modulationExaminersPrimary: Isen, Forester W.Attorney, Agent or FirmInternational ClassesH04H 1/00 (20060101)H04H 5/00 (20060101) AbstractTo permit transmission of traffic information by amplitude modulation in the medium wave band without disturbing audio signals being broadcast, a stereo pilot tone of frequency fpt below audible range is generated, as well as first and second sinusoidal signals of f1 =m1 /n⋅fpt and f2 =m2 /n⋅fpt, in which m1, m2, and n are different integers. The carrier is modulated by the stereo pilot tone and the first and second sinusoidal signals in such a manner that the phases thereof are different and further, when added, they do not essentially exceed the amplitude of the stereo pilot tone. | |
