| 摘要 |
PROBLEM TO BE SOLVED: To provide a radio terminal distance measuring system capable of narrowing a bandwidth and simplifying the configuration of a radio terminal while maintaining a high measurement accuracy.SOLUTION: A radio terminal distance measuring system includes: a reference oscillator 10 for oscillating a reference signal which is the signal of a reference frequency; a mixed signal in which first and second signals of a reference frequency which is a frequency difference between thereof are transmitted from a distance measuring device and received in a radio terminal and then mixed together; a first phase comparator 21 for performing a phase comparison with the reference signal; a VCO 23 for controlling the phase and the frequency of an output signal so as to make a phase difference zero; first and second phase synchronization circuits 30, 40 for multiplying the frequency to the output signal and generating the first and second signals, respectively; and a second phase comparator 60 for performing the phase comparison with the phase of the reference signal oscillated by the reference oscillator 10, and measures a distance with the radio terminal based on the phase difference outputted by the second phase comparator 60. |
