Algorithm for eliminating parasitic angular modulation in electromagnetic sensors

Abstract

Electromagnetic sensors of the inductive type are widely used in industrial systems, scientific research, and measuring equipment. However, during their operation, parasitic angular modulation may occur, leading to distortion of measurement results and a decrease in the accuracy of useful signal extraction. Therefore, the development of methods for compensating or eliminating the influence of such modulation is an important scientific and practical task. The paper proposes an algorithm for eliminating parasitic angular modulation in electromagnetic sensors based on extracting the central carrier frequency from an amplitude-modulated oscillation and generating a reference signal for synchronous detection. The proposed approach involves the use of an amplifier-limiter, a narrowband filter, an analog multiplier, and a low-pass filter, which together provide suppression of parasitic angular modulation and extraction of a useful low-frequency signal proportional to the parameters of the object under investigation. A structural diagram of the device implementing the proposed algorithm is presented, and spectral transformations of the signal in the main functional blocks are analyzed. It is shown that the developed approach makes it possible to reduce the influence of parasitic phase distortions and improve the quality of information extraction from the sensor output signal. The proposed algorithm has a general character and can be adapted for various types of electromagnetic measuring systems. Further development of the method is associated with its implementation using digital signal processing technologies and quadrature signal processing, which will provide additional information about the investigated object and improve measurement accuracy under low signal-to-noise ratio conditions.