Technique for effectively communicating multiple digital representations of a signal

Abstract

In a communications system implementing, e.g., an in-band on channel AM (IBOC-AM) (also known as “hybrid IBOC-AM”) scheme, multiple bit streams are used to represent an audio signal to be transmitted over one or more frequency bands including, e.g., parts of an AM frequency band for radio broadcast. These bit streams contain various and/or equivalent amounts of audio information. In an illustrative embodiment, at least one of the bit streams is a core bit stream containing core audio information. The remaining bit streams are enhancement bit streams containing enhancement audio information. The core bit stream is necessary for recovering the audio signal with minimal acceptable quality. Such quality is enhanced when the core bit stream, together with one or more of the enhancement bit streams, is used to recover the audio signal. In accordance with the invention, the AM frequency band is divided into subbands. Each of the core and enhancement bit streams is assigned to a respective one of the subbands for transmission. The assignment is conducive to an effective treatment of interference affecting the IBOC-AM system. Other embodiments may include, e.g., communications of the multiple bit streams in accordance with the invention in an IBOC-FM system, a satellite broadcasting system, etc.