| 摘要 |
PURPOSE: To shorten the time required for offset compensation and to shorten the time required for distance measurement. CONSTITUTION: Voltage/current converting means 16-18, 22-24, 28-30 and 34-36, which convert the differential voltages between the outputs of first and second amplifier means 3, 4, 7, 8 and 11-15 and the input of an integration means into a plurality of the currents, and selecting means 19-21, 25-27, 31-33, 37-39 and 50, which select the current values converted by the voltage/current converting means, are provided. In the offset operation, the values of the resistors constituting the voltage/current converting means are made smaller than values when the distance measuring signals are integrated, and the current, which is charged into an integration capacitor for offset compensation is increased. Thus, the time required for charging the integration capacitor at this time (response time) is shortened. |
