New technology that would allow radio broadcasters to transmit to listeners directly from Earth-orbiting satellites has been demonstrated under mobile reception conditions by researchers from NASA's Jet Propulsion Laboratory.

JPL engineers demonstrated direct digital radio broadcasting of compact disc-quality audio via satellite to a receiver equipped passenger van at a recent digital audio broadcasting conference in Toronto, Canada.

Under sponsorship of the Voice of America, the U.S. government's international broadcasting agency, JPL is developing a satellite radio receiver that will be turned over to industry for commercial development.

In the Toronto demonstration, JPL researchers used a NASA Tracking and Data Relay Satellite (TDRS) to beam down a compact disc radio channel in the S-band portion of the microwave spectrum to a passenger van equipped with a newly developed digital receiver and omnidirectional antenna.

Traditionally, receiving signals from satellites has relied on the use of much larger parabolic dish antennas at fixed receiving sites.

The demonstration used a digital compression method developed by AT&T to produce a 160-kilobit-per-second stereo data stream. This data stream was encoded and modulated using error protection techniques developed on the Voice of America/JPL project. The signal was transmitted at a frequency of 2089 MHz via the TDRS satellite to a van in downtown Toronto.

The successful demonstration accomplished a significant step in establishing the feasibility of satellite sound broadcasting to mobile receivers, according to the project team.

The test also pointed out some of the problems of receiving a satellite signal in a high-rise urban environment, they added. Those problems will be addressed during further research by the project.

The receiver that JPL designed and used in the demonstration has been turned over to the Electronic Industries Association for testing through the remainder of the year.

Project funding and management for the JPL effort are provided by the Voice of America, with support from NASA's Lewis Research Center and NASA's TDRS Operations Office.

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