| 摘要 |
PROBLEM TO BE SOLVED: To extend the life of an ultrasonic transducer without wastefully consuming power by measuring the wind velocity, and controlling the power supplied from a power supplying circuit to the ultrasonic transducer according to the magnitude of wind velocity. SOLUTION: A wind velocity signal converting circuit 2A1 which receives a sample signal S1 from a wind velocity sensor 1 measures the wind velocity and also compares the measured wind velocity with a prescribed threshold, and outputs a 'H' or 'L' wind velocity signal S2 according to the magnitude of the wind velocity to a power control arithmetic circuit 2A2 in the next stage. The 'H' wind velocity signal S2 is outputted when the measured wind velocity is equal to or larger than the threshold, and the 'L' wind velocity signal S2 is outputted when the measured wind velocity is smaller than the threshold. In the arithmetic circuit 2A2, a large power or small power to be supplied to an ultrasonic transducer 3 by a power supplying circuit 2B is calculated on the basis of the wind velocity signal S2, and a power control information signal S3 is outputted. When the wind velocity signal S2 is 'H', the large power is calculated, and when it is 'L', the small power is calculated. |
