| 摘要 |
PURPOSE:To decrease externally attached circuits and to improve noise resistance by sampling received infrared modulated light, performing A/D conversion, and processing digital computation. CONSTITUTION:The infrared rays, which are projected from a projecting element 2 and whose intensity is varied in response to the distance to an object to be measured, are received by a light receiving element 8. The output of the light receiving element 8 is inputted to an analog gate 50 through a light receiving amplifier 14 and a buffer amplifier 20, and sampled in synchronization with the ON and OFF cycle of the infrared modulated light. The output is imputted to an A/D converter 56 through a buffer amplifier 52. After the conversion, the output is imputted to a averaging software block 58A in a CPU58. A pickup lens 62 is moved by the output of the averaging software block 58A, and the automatic focusing is performed. |
