APPARATUS FOR PROVIDING MULTIPLE DIGITAL MODULATED SIGNALS AND METHOD OF RECEIVING MULTIPLE SIGNALS

摘要

PROBLEM TO BE SOLVED: To effectively reduce adjacent channel interference in an adjacent area using an IBOC-AM system in a system using an amplitude-modulation (AM) frequency band for communicating digitally modulated signals.

SOLUTION: Power profiles are enhanced for transmission of digitally modulated signals and the adjacent channel interference can be reduced. In accordance with the advanced power profiles, a power level of a subset of digitally modulated signals in a sub-band of the digital band becomes lower than a power level of a second subset of digitally modulated signals in a second sub-band of the digital band. At least one of the digitally modulated signals represents control information indicating selected one of the enhanced power profiles used for transmission.

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