| 摘要 |
PURPOSE:To stably hold synchronism against large noise and further to hardly generate out-of-synchronism by correlating two pairs of pseudo noise codes and received signals with different phases and controlling a voltage controlled oscillator(VCO) based on a synthetic output for synthesizing a correlation value. CONSTITUTION:An input signal is inputted to four correlators (multipliers) 10, 20, 30 and 40, then, at these correlators, those signals are multiplied with four PN codes of different phases outputted from a pseudo noise generator (PN code generator) 13. Concerning four PN codes of different phases, there is the phase difference of one chip between the adjacent codes on a stage. The outputs of the correlators 10, 20, 30 and 40 provided by multiplying the PN code phases at the same degree of advance and delay to the input signal are passed through envelope detectors 11, 21, 31 and 41, envelope-detected and inputted to differentiators 12, 31 and 41 later so as to provide a differential signal. Two provided differentiator outputs are added by an adder 15, that output is waveform-shaped through an S characteristic shaping circuit 16 and used as the control signal of a VCO 17 later. |
