| 摘要 |
<p>A wide band, wide area FM-SCA radio has central station (20) that transmits multiple audio signals and digital data signals through a satellite network (22) to FM stations participating in the system. Each FM station demodulates and time multiplexes the audio and digital signals with a control signal to form a first baseband waveform having a frequency range corresponding to the SCA frequency bandwidth. The first baseband waveform and a regular FM baseband waveform are combined into a composite band waveform that is single-sideband modulated onto the station carrier for retransmission to FM-SCA receivers (27) in the coverage area. Each FM-SCA receiver (27) demodulates the received signal and separately processes the regular FM-signal (32), the FM-SCA- audio signals (34) and the FM-SCA digital data signal (36). A user interface is provided for audio output selection.</p> |
