| 摘要 |
PROBLEM TO BE SOLVED: To solve such problems that it is not possible to detect the passage of a vehicle due to the irregular reflection of ultrasonic waves or a compact vehicle or the like in a method for detecting the passage of a vehicle with ultrasonic waves, and that maintenance is required due to the dirt of a lens in optical detection, and that there is the influence of a noise in radio waves in a conventional traffic counting method and device. SOLUTION: A waveguide bar 5 is embedded in a road 4, and a ultrasonic wave oscillator 6 is connected to the waveguide bar 5, and an oscillation output is applied from an impedance analyzer 7 to the ultrasonic wave oscillator 6, and the change of a resonance frequency is detected from the change of the oscillation output, and the change of the resonance frequency is detected by a discrimination detecting circuit 8. The change of a resonance frequency detected by the discrimination detecting circuit 8 is detected, and the presence/absence of the passage of the vehicle is counted by an incorporated counting circuit, and the counted value is transmitted from an antenna 10 by a transmitting circuit 9. A power is supplied from a power source 11 to the impedance analyzer 7, the discrimination detecting circuit 8 and the transmission circuit 9. COPYRIGHT: (C)2005,JPO&NCIPI
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