Title: Compatible AM stereo broadcast system

Abstract: A compatible AM stereo broadcasting system is disclosed in which the signal is a carrier having an amplitude directly variable with monoaural or sum (L+R) information, and having an instantaneous phase .phi. varying as a function of the resultant amplitude of the sum information (L+R) and difference information (L-R) which are established in a preselected phase relationship (quadrature). In a stereo receiver, L and R or the sum and difference signals may be restored by dividing the signal by the cosine of the angle .phi., and in a monaural receiver, the sum signal alone is detected.

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Other info:

Inventors: Parker, Norman W. (Wheaton, IL, US)
Hilbert, Francis H. (Addison, IL, US)

Application Number: 007733
Filing Date: 1979-01-30
Publication_date: 1980-08-19
Assignee: Motorola, Inc. (Schaumburg, IL)
Primary Class(es): 381/16 455/61, 455/91
Other Classes:
US Patent Ref:

3067293	Dec, 1962	Moore	179/1.
3068475	Dec, 1962	Avins	325/36.
3167614	Jan, 1965	Holt et al.	179/1.
3218393	Nov, 1965	Kahn	325/36.
4079204	Mar, 1978	Takahashi et al.	325/36.

Other Refs:
Primary Examiner: Bookbinder, Marc E.
Assistant Examiner:
Attorney: Parker; Margaret Marsh, Gillman; James W.