| 摘要 |
PURPOSE:To make it possible to obtain a high SN ratio and adaptability by integrating the outputs of a light detection by switching and driving the light source with timing that is synchronized with the switching. CONSTITUTION:The output voltage V0 of an integrator 6 is set at V0=0, and the output current of a light diode 4 is integrated at the integrator 6 for time T1 set by means of a switch 5. Next light sources 2 and 3 are lighted at the time t1, and at the same time the output current of the light diode 4 is integrated in the reverse direction for time T2. Further, the light sources 2 and 3 are turned off at time T2 and during this time the integration is stopped. The output voltage V0 during the time T3 shows true intensity of the reflected light without external influences. When the integrator 6 is reset by the switch 5, it returns to the initial state (time=T4). With this arrangement the influence of the external light is removed, and the measurement of the amount of light can be made with an excellent SN ratio and also with rapid response. |
