U.S. patents available from 1976 to present.
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Digital audio broadcasting system

Patent 5283780 Issued on February 1, 1994. Estimated Expiration Date: Icon_subject February 1, 2011. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

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Inventors

Assignee

Application

No. 598396 filed on 10/18/1990

US Classes:

370/312, Message addressed to multiple destinations370/314, Using time division multiplexing370/436, Combined time and frequency assignment375/344, Automatic frequency control381/2, Broadcast or multiplex stereo455/65, Anti-multipath455/257, Automatic455/260, Phase lock loop or frequency synthesizer714/786Forward error correction by tree code (e.g., convolutional)

Examiners

Primary: Olms, Douglas W.
Assistant: Ton, Dang

Attorney, Agent or Firm

International Class

H04J 004/00

Abstract

A digital audio broadcasting system that is capable of providing a large number of high quality stereophonic channels to mobile receivers in an environment with severe multipath delay and fading. Optimum combination of frequency and time diversity to guarantee robust performance in the mobile channel, with its multipath delay and frequency-selective fading effects. The system is based upon a dynamic single channel per carrier assignment of each stereo channel to many carriers. Intersymbol interference degradations caused by multipath delay are mitigated via an adaptive equalizer in the receiver. This dynamic single channel per carrier system preserves the simplicity inherent in the single channel per carrier assignment while it incorporates the ability to address frequency-selective fading by providing substantial frequency diversity. The frequency diversity is achieved via a slow frequency hop implementation in which the assignment of a number of stereo channels to an equal number of carrier frequencies is changed periodically. The system offers the simplicity of single channel per carrier assignment of stereo channels while it achieves the powerful performance benefits of frequency diversity and adaptive equalization for the mobile channel.

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