| 摘要 |
PURPOSE:To continuously measure low and high concn. components to be measured with good accuracy using only one detector, by respectively supplying sample gases containing low and high concn. components to be measured while modulating both of them at mutually different frequencies using comparing gases. CONSTITUTION:Fluid modulation means 4, 5 respectively modulate a sample gas SL containing a low concn. component to be measured and a sample gas SH containing a high concn. component to be measured at mutually different frequencies using comparing gases R and both gases are simultaneously and continuously supplied to only one detector at a constant cycle so that the flow rate of the sample gas SL is more than that of the sample gas SH. The output signal from the detector 1 is separated into the signal components of respective modulation frequencies to the sample gases SL, SH and both components are rectified and smoothed to make it possible to simultaneously measure the concns. of the low and high concn. components to be measured. |
