DX4040 INSTRUCTION AND OPERATING MANUAL (E2.04)
infrared source. The modulated infrared radiation passes through the sample cell where
sample gas absorbs certain wavelengths of the radiation. The detector detects the
transmitted infrared radiation. The A/D converter digitizes the signal. The on-board
digital signal processor (DSP) performs a mathematical Fourier transform on the
digitized interferogram resulting in a spectrum.
Fast Fourier Transform (FFT) is used to compute the spectrum from the interferogram.
The FFT result is a transmittance spectrum. The absorbance spectrum is the ratio of
the sample spectrum (transmittance spectrum) to the background spectrum. (The
absorbance spectrum is computed from the transmittance spectrum). Gasmet uses the
Calcmet Lite
software to display the concentrations of the components present in the
sample gas from the absorbance spectrum.
Figure 7.
Basic structure of the Gasmet DX4040 analyser.
The data and signal processing electronics control the operation of the analyser. A PDA
is used as a master device to communicate with the Gasmet DX4040 analyser.
A unique part of the analyser is the Gasmet Technologies Oy's GICCOR (an acronym
for 'Genzel interferometer with a cube corner retroflector') interferometer. It is rugged
and withstands the demanding environmental conditions of non-laboratory environment.
The GICCOR interferometer modulates the infrared radiation coming from the infrared
source, as discussed previously.
4.2 Gasmet DX4040 Technical Specifications
4.2.1
General Parameters
It is recommended that all instruments operate in the following environmental
conditions:
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