| 摘要 |
<p>PURPOSE:To stably detect infrared rays without deteriorating the resolution by fetching an AC output at a point comparable of the waveform of AC outputs with each other varied by the infrared-ray quantity. CONSTITUTION:A microcomputer 16 generates a driving voltage to a chopper C, and also, generates a start signal to an A/D converter 17 by a period of 1/2 thereof. The converter 17 fetches the output voltage of a full-wave rectifying circuit 13 by this timing, brings it to A/D conversion, and outputs carbon dioxide gas concentration as the digital value to the computer 16. The computer 16 executes the display and the control of gas concentration, based on this data. Also, the converter 17 operates in the same position of a ripple every time, and compares this value, therefore, a smoothing circuit becomes unnecessary. Especially, the timing by which the converter 17 inputs the output of the circuit 13 is made by the computer 16, therefore, there is no shift of synchronization, and high accuracy is obtained.</p> |
