| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a gas concentration measurement instrument employing a TDLAS measurement method, which is capable of phase-sensitive detection by digital processing using an integer arithmetic device. <P>SOLUTION: In the gas concentration measurement instrument relating to the present invention, an interval moving average of data in one period of a modulation frequency f is first calculated from an output signal from a multiplier 62 to remove AC components being integral multiples of the modulation frequency f, which are included in an input signal. Therefore, DC components are relatively increased in an output signal of a digital filter 63, so that extraction of DC components in a digital low pass filter 64 is facilitated to be able to perform phase-sensitive detection with sufficient accuracy in spite of the use of digital processing based on integer arithmetic. <P>COPYRIGHT: (C)2012,JPO&INPIT |
