Patent ID: 6456645
Filing Date: 2002-09-24
Classification: H04B

Abstract:
A digital audio transmission system comprising:a stationary transmitter section including: interface means for receiving a signal from an audio source and generating transmitter digital audio data to represent that signal; channel encoding means for generating transmitter serial digital data based on said transmitter digital audio data; radio-frequency transmitter means including radio-frequency oscillator and frequency modulation means for generating a radio-frequency signal that is frequency-modulated with a periodic transmitter spreading signal wherein the frequency of said transmitter spreading signal is at least as high as the bit rate of said transmitter serial digital data, and transmitter amplitude modulation means for amplitude-modulating said frequency-modulated radio-frequency signal with said transmitter serial digital data resulting in an amplitude-keyed radio-frequency signal that is spread in frequency; and transmitter antenna means for transmitting said amplitude-keyed radio-frequency signal as electromagnetic waves; and a receiver section including: radio-frequency receiver means including receiver antenna means for receiving said electromagnetic waves and resulting in a receiver radio-frequency signal, amplifier means for amplifying said receiver radio-frequency signal, and data recovery means for generating receiver serial data corresponding to said transmitter serial data; channel decoding means responsive to said receiver serial digital data for generating receiver digital audio data equal to said transmitter digital audio data; and digital-to-analog converter means for generating an analog signal based on said receiver digital audio data.