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MEASURING PRINCIPLE
2 - 5
ETC00781(1) Series 100 e 10/2001
2.1.3 Technique
The broadband emission from two IR sources (in the case of dual channel analyzers) passes
through the chopper blade, then, if IFC, through combinations of interference filters, if
optopneumatic principle depending on application through an optical filter (reduction of influ-
ences) and enters the analysis cells. The light transmitted through these cells is focused by filter
cells onto the according detector. The preamplified detector output signal is sent to microprocessor
circuitry, which converts the analytical signals to results expressed directly in physical concentra-
tion units (Vol.-%, ppm, mg/Nm
3
etc.).
IR MEASUREMENT
Duplex filter disc
Analysis cell
(undivided)
Pyroelectrical detector
(solid-state detector)
Adapter cell
(high measuring range)
Gas detector
Filter cell
Light source
Preamplifier
Filter cell
Analysis cell reference side
Analysis cell measuring side
Preamplifier
Fig. 2-3: Principle Representation
Chopper blade
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