| 摘要 |
Light from IRED 14 is projected onto a target, and reflected light is detected by position sensitive detector (PSD) 3. PSD 3 output is amplified 20, 30, 40, 50 under control of control circuit 80 and the amplified signal is integrated 60. Initially the capacitors 63, 64 of the integrator 60 are switched 63, 64 (again under the control of control circuit 80) to be in parallel; after the integrator 60 output exceeds a first threshold, the capacitors are switched to be in series. This reduces the capacitance of the integrator 60 and increases the voltage output, and hence reduces the time to carry out a distance measurement. <IMAGE> |
