Use of a resonant sensor for differential air pressure measurements

This paper describes a differential resonant pressure sensor formed by a ferromagnetic cylindrical resonator with electromagnetic excitation. The frequency of the resonator corresponds to the pressure difference between the inner and outer space of the resonator and the level of absolute air pressure on which this difference is created. The sensor can therefore be used for measuring air speed, and its frequency output can be used for precise signal processing using a counter. A disadvantage of this application lies in the dependence of the output frequency on the absolute air pressure level, and therefore on the altitude at which the air difference and therefore the air speed are measured. A solution to these problems is described in the following text.