| 摘要 |
PROBLEM TO BE SOLVED: To detect the deviation of a reference frequency of transmission and reception even in the case of a low S/N by detecting a frequency having the maximum value between the power frequency spectrum of an output of a 1st restoration circuit and the power frequency spectrum of an output of a 2nd restoration circuit. SOLUTION: A 1st restoration circuit 7 restores spread spectrum to an intermediate frequency chirp signal r (t) 3 which is obtained via frequency conversion of a transmission chirp signal. A 2nd restoration circuit 8 restores spread spectrum after execution of a prescribed frequency offset of the intermediate frequency chirp signal r (t) 3. A detecting part 9 detects a frequency having the maximum value among the power frequency spectrum of an output of the circuit 7 and the power frequency spectrum of an output of the circuit 8. Thus, a signal can be detected even when a reception S/N is low, the deviation of a reference frequency of transmission and reception can be corrected with the detected signal and a reception frequency and a clock timing can be quickly synchronized. |
