Features of Signal Processing in the Absorption Gas Analyzer when Measuring Low Concentrations

For measuring low concentrations of vapors and gases the author examines features of signal processing occurring in absorption gas analyzer,which fixes the test region of the spectrum using interference filters. In order to minimize measurement errors with reasonable accuracy it is necessary to determine the ratio of a small change in the voltage difference to the larger value of the reference voltage (corresponding ratio for the two values close to unity). Differential method of measurement has the advantage in the case of deterministic signals. However at low concentrations practical implementation of such measurements comes up against difficulties, that must be considered at structural design and algorithms development for signal processing of absorption analyzer using interference filters. The necessity of a probabilistic approach is shown in relation to emerging signals in the form of acentric random variables when measuring low concentrations. For the purpose of obtaining reliable results measurement conditions have been formalized for further research of emerging random error and systematic inaccuracy. Required problems are formulated for signal processing algorithm of gas analyzer.

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