Compatible transmission techniques for FM stereophonic radio and television
Patent 4602380 Issued on July 22, 1986. Estimated Expiration Date: 
January 4, 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.
January 4, 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 References 3067292 Compatible stereophonic receiver Compatible AM stereophonic system Signal compression and expansion system FM Stereophonic system incorporating companding of difference signal Signaling system for FM transmission systems Patent #: 4534054 InventorAssigneeApplicationNo. 06/688940 filed on 01/04/1985US Classes:381/13, Antinoise329/327, Input signal split into plural signals332/120Including amplitude modulationExaminersPrimary: Isen, Forester W.Attorney, Agent or FirmInternational ClassesH04H 5/00 (20060101)H04B 1/16 (20060101) AbstractA stereophonic broadcasting system incorporating companding of the difference signal in which both the usual difference signal and a compressed version of the difference signal are transmitted to one or more remote receivers. At the receiver the usual difference signal and the compressed difference signal are combined and the resulting signal then expanded to obtain a noise-reduced difference signal for matrixing with the sum signal to obtain the original left and right signals. Utilizing both difference signals increases the effective level of the received difference signal by 6 dB, whereas the noise is increased only 3 dB, for a net improvement of 3 dB in signal-to-noise ratio. Utilization of both difference signals at the receiver also permits compression of the difference signal according to any desired compression law. | |
