| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an infrared-ray receiving device that excludes influence of noise light such as sunlight. <P>SOLUTION: In each light receiving circuit 70, a high-frequency signal based upon infrared rays incident on a photodiode 50 is inputted to an add circuit 84 through a preamplifier circuit 78, a buffer amplifier circuit 80 and a switching circuit 82. Further, a high-frequency signal having been amplified by the preamplifier circuit 78 is inputted to a comparator circuit 90 as well through a band-pass filter 86 and a rectifier circuit 88. When noise light is incident on the photodiode 50, the output level of the comparator circuit 88 rises above a prescribed reference level. In this case, the comparator circuit 90 turns off the switching circuit 82. When the noise light is not incident, the switching circuit 82 is turned on. Namely, when noise light is incident on any photodiode 50, the output of the light receiving circuit 70 corresponding to the photodiode 50 is automatically invalidated. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
