SPREAD SPECTRUM COMMUNICATION DEVICE

摘要

PROBLEM TO BE SOLVED: To speed up acquisition of clock synchronism and reduce jitters in a clock by making a phase comparison between a convolution output and a code timing signal at a frequency which is double as high as a code cycle and acquiring the clock synchronism. SOLUTION: A code generating circuit 103 generates a spread code series and generates the code cycle of the spread code series and code generation timing of frequency which is double as high as the code cycle. A voltage- controlled oscillator(VCO) 106 generates a clock which drives the code generating circuit 103. A correlator 111 obtains a correlation with a received signal and a phase compactor 110 makes a phase comparison between the output of the correlator 11 and the timing signal of frequency double as high as the code cycle to acquire the synchronism. Then a phase comparing circuit 104 detects the time difference between the output of the correlator 11 and the timing signal of the code cycle and a reset circuit 105 generates code reset timing from the time difference. Thus, the phases of the convolution output and code timing signal are compared with each other at the frequency which is double as high as the code cycle to acquire the clock synchronism.