| 摘要 |
PROBLEM TO BE SOLVED: To stably detect concentrations of a high concentration gas and a low concentration gas, while restraining a circuit scale from getting large, by using one semiconductor laser, and to restrain responsiveness from getting worse. SOLUTION: A switching control part 40 switches timing of frequency modulation to modulate a frequency within a partial period scanned with a wavelength of a laser beam, and a control processor 50 calculates the concentration of the high concentration gas, based on photoreceived luminous energy output from an amplifier 43, and calculates the concentration of the low concentration gas, based on a 2f component detection signal output from an amplifier 48. COPYRIGHT: (C)2009,JPO&INPIT
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