Modulated oxygen-flux method and apparatus to improve the performance of a calorimetric gas sensor

摘要

A method and apparatus is provided for modulating the flux of oxygen impinging on a calorimetric gas sensor. The method and apparatus are based on modulating the oxygen concentration of a gas mixture (32) presented to the microcalorimeter between a predetermined high level and at a substantially zero value to create a modulated output to reduce the noise of the sensor and to eliminate its zero-offset. In the apparatus (10), the oxygen supply is modulated by an oxygen "pump" cell (26) located in the wall of a chamber (14) containing the gas sensor (18). The cell is controlled by signals applied to electrodes (28).