| 摘要 |
PURPOSE:To provide a temperature correcting device for measurement of sound transmitting time which is not followed by increase in cost and size and has high accuracy. CONSTITUTION:A temperature correcting device for measurement of sound wave transmitting time is connected to the rear stage of an HC sensor 1 to output frequency signals at frequencies of fixed number times of sound wave transmitting time to be measured and provided with a pulse generator 11 to generate pulse signals to be triggered at the frequency of the frequency signals, a resistor 13 to resistively dividing the pulse signals generated from the pulse generator 11 and linear temperature sensitive resistor 12, and an integrator to integrate the pulse signals divided resistively. Also, the resistance of the linear temperature sensitive resistor 12 varies linearly according to increase in temperature, and a variation in voltage value of the resistively divided pulse signals due to temperature rise is offset by a variation in sound velocity due to temperature rise. |
