Patent ID: 6078608
Filing Date: 2000-06-20
Classification: H04B

Abstract:
A spread spectrum communication apparatus comprising:a spread spectrum modulator for converting transmission data into a spread spectrum signal using a predetermined code sequence; anda spread spectrum demodulator for demodulating a received spread spectrum signal to original data,wherein said spread spectrum demodulator comprises:a correlated signal acquisition circuit for demodulating said received spred spectrum signal to acquire a correlated signal;first and second delay circuits for delaying an output signal of said correlated signal acquisition circuit; anda first adder circuit for adding the output signal of said correlated signal acquisition circuit and an output signal of said first delay circuit; anda second adder circuit for adding the output signal of said correlated signal acquisition circuit and an output signal of said second delay circuit,said first delay circuit delaying an input signal by a time period expressed by T+(.+-.n+5.times.a/8)/fc, where T represents one period of a received signal to be demodulated; fc represents a carrier frequency of a signal inputted to said correlated signal acquision circuit; n represents an integer including zero equal to or less than a value of (2.times.carrier frequency fc/chip rate); and a is a value in a range of 1/2.ltoreq.a.ltoreq.3/2, andsaid second delay circuit delaying an input signal by a time period expressed by T+(.+-.m-5.times.a/8)/fc, where m represents an integer including zero equal to or less than the value of (2.times.carrier frequency fc/chip rate).