| 摘要 |
PROBLEM TO BE SOLVED: To shorten the initial capture time of a received signal and to expand the fluctuation of the capture range enable frequencies by performing correlative operation before detection by arranging an intermediate frequency(IF) correlator, with which the output of a frequency converter and the output of a reference signal generator are correlated, outside a phase lock loop(PLL). SOLUTION: A frequency converter 9 converts the frequency of output of a reception antenna 8 to the signal of an IF band and a reference signal generator 13 generates a reference signal at IF while having the same waveform as a reference signal sent from the transmission side. Besides, an IF correlator 12 correlates the output of the frequency converter 9 and the output of the reference signal generator 13 and supplies its output to quadrature detector 14 as an input to be detected. In this case, the IF correlator 12 is arranged outside the PLL, for which a voltage controlled oscillator(VCO) 15 and a frequency duplexer 16 are connected and arranged in the form of loop, and a carrier wave for quadrature detecting the output of the frequency converter 9 is reproduced from the output side of the VCO 15 included in the PLL. |
