摘要 |
In a multistage active infrared sensor, the light emitters 11A, 11B, 11C emit infrared signals which contain distinct channel information. These light emitters 11A, 11B, 11C emit the infrared signals at different timings from each other. This sensor judges whether the infrared signals received by light receivers 12A, 12B, 12C contain channel information of opposite light emitters 11A, 11B, 11C. The sensor cancels any infrared signal which does not contain the channel information of the opposite light emitters 11A, 11B, 11C.
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