| 摘要 |
PROBLEM TO BE SOLVED: To prevent errors in detection based on popcorn noise, instantaneous impact from outside, or electrical impulse noise. SOLUTION: A first amplification circuit 5a amplifies a voltage signal in a first band of frequencies centered around 1 Hz, and a second amplification circuit 5b amplifies a voltage signal in a second band of frequencies of approximately several dozen Hz to 100 Hz. A first comparison circuit 14a makes a comparison between the voltage signal output from the first amplification circuit 5a and a predetermined threshold Vr3, and a second comparison circuit 14b makes a comparison between the voltage signal output from the second amplification circuit 5b and a predetermined threshold Vr4. A first pulse-width discrimination circuit 19a discriminates the pulse width of the output signal of the first comparison circuit 14a, and a second pulse-width discrimination circuit 19b discriminates the pulse width of the output signal of the second comparison circuit 14b. Moreover, a determination section 20 determines, in accordance with the two output signals of the pulse-width discrimination sections 19, whether or not a human body is being detected. COPYRIGHT: (C)2008,JPO&INPIT
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