| 摘要 |
PURPOSE:To prevent the generation of error signals due to popcorn noise, by combining two pyroelectric infrared-ray detectors with a gate circuit. CONSTITUTION:The pyroelectric infrared-ray detectors 24, 25 are adjacently arranged in parallel so as to detect infrared-rays from the same irradiating body simultaneously. The outputs of both the detectors are applied to a gate circuit 34 consisting of a transistor 35 and a bias resistor 36 through respective amplifiers 30, 31. Subsequently, an output from the gate circuit 34 is applied to a control circuit 37. Since both the detectors 24, 25 do not generate popcorn noises simultaneously, a noise is gated by the gate circuit 34 and prevented from being supplied to the control circuit 37 even if the noise is generated in the detector 24. Thus the generation of error signals due to the popcorn noises can be prevented. |
