Study of the frequency characteristics of a tremor analysis system based on a capacitive proximity sensor

Abstract

The technique of tremor control using a capacitive sensor to ensure high sensitivity and stability of measurement results requires the correct selection of operating parameters of the system. Study of the influence of operating parameters, selection of the optimal antenna design and frequency-setting elements in a system for analyzing tremor of the upper limbs based on a capacitive proximity sensor. The tremor sensor being developed is based on a rectangular pulse generator, the generation frequency of which depends on the capacitance. The dependence of the generation frequency on the distance between the antenna and the limb was studied for various values of capacitance and resistance of the resistor in the generator circuit. It is proposed to use a circuit without a capacitor in the frequency-setting RC circuit, which allows for the largest frequency increment and clearly detects tremor with both large and small amplitude. An experimental study of various antenna designs was carried out. It has been shown that when using a helical antenna, the maximum sensitivity of the sensor is observed with the smallest diameter, however, the use of a small diameter reduces the area of interaction between the electric field and the tissues of the human limb. The electromagnetic method is a promising method for digitizing tremor, allowing for rapid non-contact diagnostics. The experimental results obtained make it possible to justify the choice of optimal parameters for the tremor analysis system.