| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a gas detection apparatus capable of keeping zero point stability and detecting a gas leak with high accuracy regardless of the presence of various noises such as partial concealing on the way of detection or the like. SOLUTION: An output signal is inputted to a modulation signal adjusting circuit by a signal generating circuit 24, and a modulation signal is outputted to respective laser diodes 16A, 16B so that the laser diodes 16A, 16B become an inverse phase to output modulation lights from the laser diodes. Measuring light is formed from the modulation lights outputted from the laser diodes by a branching filter 18 and three wave synthesizers 20A, 20B, 20C, outputted to the target gas atmosphere of a probe part 14, and received by a light receiver 36. Only a modulation component is extracted by a synchronizing detection circuit 26 to detect gas.</p> |
