| 摘要 |
PURPOSE:To simplify the circuit constitution and to reduce causes of errors, by imparting the signals from two AC amplifiers to two logarithmic amplifiers, supplying the output signals to a subtractor, and obtaining a distance signal. CONSTITUTION:Light from a light source is projected to a point, the distance to which is to be measured, through a lens on the light emitting side. The light spot of the reflected light is formed on a light receiving surface of a semiconductor position detector 1 by using a lens on the receiving side. Output currents I1+Ib and I2+Ib of the detector 1 are imparted to current/voltage converters 2 and 2' and the AC amplifiers 3 and 3', and the signals which are proportional to I1 and I2 are obtained. The signals from the amplifiers 3 and 3' are imparted to the logarithmic amplifiers 20 and 21, and their outut signals are supplied to the subtractor 22. Then the signal proportional to In(I1/I2) is obtained. The output signal of the subtractor 22 is the distance signal. Thus the circuit constitution is simplified and the causes of the errors are reduced. |
