Receiver for a spread spectrum communication system having a time-multiplexed convolver

A convolver for convolving an input signal with a time reversed-time multiplexed reference signal comprising:

• a piezoelectric substrate;
• a first interdigital transducer for launching a first surface acoustic wave along a first path on the surface of said substrate in response to said input signal;
• a second interdigital transducer for launching a second surface acoustic wave along said first path on the surface of said substrate in response to said time reversed-time multiplexed reference signal, said first path defining an interaction region of said first and second surface acoustic waves;
• a segmented summing bus disposed intermediate said first and second interdigital transducers, said segmented summing bus having a plurality of equally spaced fingers extending into said interaction region;
• a ground bus having a plurality of filler segments extending into said interaction region between said equally spaced fingers;
• and
• a pair of acoustic horns, one disposed intermediate said segmented summing bus and each of said first and second interdigital transducers.

A spread spectrum receiver for demodulating a M-ary orthogonal keying data modulated signal having a predetermined chipping rate comprising an input amplifier for converting the received M-ary orthogonal keying data modulated signal to an input signal, convolver means for convolving said input signal with time reversed reference signals to generate discrete samples, and means for extracting the data from said samples characterized by:

• reference signal generator means for generating time reversed-time multiplexed reference signals;
• a time-multiplexed convolver for convolving said input signal and said time reversed-time multiplexed reference signals to generate M time multiplexed samples where M is equal to the number of orthogonal keying functions of said received M-ary orthogonal keying data modulated signal;
• demultiplexer means for separating said time multiplexed samples into M discrete samples;
• and
• means for comparing said M discrete samples to extract said data.

A spread spectrum communication system comprising:

• transmitter means for transmitting a pseudo random noise, phase modulated signal having a predetermined chip rate and modulated with data desired to be sent;
• receiver input means for generating a convolver input signal at a predetermined intermediate frequency in response to receiving said pseudo random noise, phase modulated signal;
• reference signal generator means for generating time reversed-time multiplexed reference signals having said same pseudo random noise phase modulated signal in a time reversed sequence;
• time-multiplexed convolver means for convolving said convolver input signal with said time reversed-time multiplexed reference signal to generate time multiplexed output samples;
• demultiplexer means for separating said time multiplexed output samples to generate discrete samples, each discrete sample corresponding to one of said binary phase modulations;
• and
• means for comparing the amplitudes of said discrete samples to recover said data.