| 摘要 |
PURPOSE:To precisely measure a long distance without being affected by the influence even when the frequency of a projected light is changed by comprizing an adder adding the respective output signals of delay circuits together and calculating a distance by means of the output signal of the adder. CONSTITUTION:This device comprises a light projecting means 2 irradiating an object 5 with a pulse light, a light receiving means 7 receiving the light reflected by the object 5 of the projected light from the light projecting means 2 and current/voltage converting circuits 10, 20 converting the output current of the light receiving means 7 to a voltage. The device is provided with one and more delay circuits 12, 22 delaying the output signals of the current/voltage converting circuits 10, 20 by the delay time of the integer multiple of the period of the light projecting signal and adders 13, 23 adding the respective outputs of the delay circuits 12, 22. By providing plural delay circuits having the delay times of the integer multiple of the light projecting period and mutually superposing the out-puts in the same period, a random noise component is canceled and a signal without distortion is obtained. The signal is sampled with a prescribed timing, analog/digital converted and arithmetically processed in a CPU 3 so as to obtain the result of distance measurement. |
