| 摘要 |
<p>PURPOSE:To eliminate wrong information and misinformation and to improve the reliability by detecting the peak of the detection output of twin elements. CONSTITUTION:A detection part 10 which has a couple of twin elements detect heat rays radiated by a passing human body in a specific warning area. Its output is amplified 12 and converted by an absolute value circuit 14 into an absolute value signal which has amplitude variation of one polarity. Further, a clip circuit 22 extracts a signal waveform exceeding a specific level from the signal and remove noise components which are lower than the level. Then a peak detecting circuit 24 detects the peak, a timer circuit 26 outputs a next signal when obtaining the signal within a specific time a predetermined constant time after the 1st peak signal is obtained, and a warning circuit 20 generates an alarm. Thus, the peak timing of the detection output is accurately detected and compared with a timer set time to detect the passage of the human body; and the detection frequency based upon the passage of the human body is accu rately discriminated from respective noises and wrong information and misinfor mation are eliminated.</p> |
