Abstract:
The presented work deals with a feasibility study related on the implementation of digital Giant Magneto-Impedance (GMI) magnetometer (sensor operating in closed-loop). The proposed measurement chain mainly includes an analog- to-digital conversion (ADC) and a digital amplitude demodulation based on a Digital Down Conversion (DDC). In this configuration, the voltage is digitized as close as possible to the sensing element. The DDC include digital mixer and filtering. The transfer function of the overall sensor in open-loop is modelled so as to discuss the stability of the digital magnetometer regarding the processing delay and the sensitivity. Simulations were performed using Matlab-Software with a different set of parameters of the sensor in order to discuss the stability of the magnetometer according to the time delay. The obtained results showed that with a careful adjustment of the sensor sensitivity and the decimation ratio of the digital filter associated with the digital demodulation, the digital magnetometer could be stable in closed-loop.
Keywords:
Digital demodulation, Magnetometer, Processing time-delay, Giant Magneto Impedance (GMI) sensor.
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