Patent ID: 7412294

Claim:
A wireless digital audio system comprising: at least one audio source to produce an audio output; at least one digital portable audio transmitter operatively coupled to said at least one audio source, said at least one portable audio transmitter comprising: a first analog low pass filter receiving audio output from said at least one audio source; a digital low pass filter; an analog-to-digital converter (ADC) operatively coupled between said first analog and digital low pass filters; a first encoder receiving output from said digital low pass filter and being configured to reduce intersymbol interference (ISI); a second channel encoder operatively coupled to said first encoder and adapted to reduce transmission errors; a digital modulator operatively coupled to said second channel encoder; and a differential phase shift key (DPSK) module receiving output from said digital modulator and a unique user code bit sequence and being configured for direct sequence spread spectrum (DSSS) communication, said DPSK module transmitting a corresponding DSSS signal having said audio output and the unique user code bit sequence; at least one portable audio receiver configured for digital wireless communication with said at least one portable audio transmitter and utilizing an embedded fuzzy logic detector wherein the fuzzy logic detector activates fuzzy logic rules and performs a defuzzification operation in response to a received user code to optimize digital signal processing, said at least one portable audio receiver comprising: a band pass filter (BPF) configured to process said transmitted DSSS signal; a direct conversion module receiving output from said BPF and being configured to capture the correct unique user code bit sequence embedded in said processed DSSS signal; a digital demodulator adapted to process output from said direct conversion module; a Viterbi decoder operatively coupled to said digital demodulator and generating a corresponding digital output; a source decoder processing said digital output from said Viterbi decoder and being configured to decode the digital signal encoded by said first encoder; a second analog low pass filter; and a digital-to-analog converter (DAC) operatively coupled between said source decoder and said second analog low pass filter, said second analog low pass filter generating an audio output corresponding to the decoded and converted digital signal; and at least one module adapted to reproduce said generated audio output, if the unique user code bit sequence is recognized, said audio output having been wirelessly transmitted from said at least one audio source without interference from other users or wireless devices when operated within a shared space containing multiple users of wireless devices utilizing code division multiple access (CDMA) communication.