| 摘要 |
PURPOSE:To improve measuring accuracy by arranging a pair of ultrasonic transducer, orthogonally intersecting plural pipes having an orthogonal end surface to the axis of the pipe and finding out wind speeds in respective pipes to measure the wind direction from the direction of the sum of the vectors and the wind speed from the absolute value of the sum of the vectors. CONSTITUTION:When an ultrasonic wave is transmitted from a transducer US1 into a pipe having a wind speed Vx on the basis of an output signal (a) from a transmission oscillator OSC, the ultrasonic wave is converted into an electric signal by a transducer US2, A signal (b) amplified by a receiving circuit R is converted into a square wave (c) by a circuit RW2, the square wave (c) is expanded at its pulse width by a counter circuit C2 and a flip flop circuit FF and then inputted to a phase difference detecting circuit PD as an input signal (d). A signal (f) obtained by converting a part of the signal (a) into a square signal (e) by a circuit RW1 and extending its pulse width by a counter circuit C1 is inputted as the other input signal to the circuit PD. When the signals (a) and (c) have the same pulse width, a phase difference between the signals (f) and (d) is detected by the circuit PD. The output signal (h) of the circuit PD is converted into an analog signal to obtain the wind speed V. A wind direction/ speed calculating circuit CAL calculates the wind speed V0 and the wind direction thetafrom output V0costheta and V0sintheta. |
