METHOD AND APPARATUS FOR AM COMPATIBLE DIGITAL BROADCASTING

A broadcasting method for simultaneously broadcasting analog and digital signals in a standard AM broadcasting channel is provided by: broadcasting an amplitude modulated radio frequency signal having a first frequency spectrum, wherein the amplitude modulated radio frequency signal includes a first...

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Bibliographische Detailangaben
Hauptverfasser: DAPPER, MARK, JAMES, GEILE, MICHAEL, JOSEPH, CARLIN, BARRY, WALTER
Format: Patent
Sprache:eng ; fre ; ger
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Zusammenfassung:A broadcasting method for simultaneously broadcasting analog and digital signals in a standard AM broadcasting channel is provided by: broadcasting an amplitude modulated radio frequency signal having a first frequency spectrum, wherein the amplitude modulated radio frequency signal includes a first carrier modulated by an analog program signal; and simultaneously broadcasting a plurality of digitally modulated carrier signals within a bandwidth which encompasses the first frequency spectrum, each of the digitally modulated carrier signals being modulated by a portion of a digital program signal, wherein a first group of the digitally modulated carrier signals lying within the first frequency spectrum are modulated in-quadrature with the first carrier signal, and wherein second and third groups of the digitally modulated carrier signals lie outside of the first frequency spectrum and are modulated both in-phase and in-quadrature with the first carrier signal. Transmitters and receivers which operate in accordance with the above method are also provided.