Implementation of the Digital-Down-Conversion (DDC) and software for the optimization of the Giant Magneto-Impedance (GMI) sensors

This paper deals with the implementation of the Digital-Down-Conversion (DDC) for signal demodulation and processing in Giant Magneto-Impedance (GMI) sensors. In this approach, a direct Analog-to-Digital Conversion (ADC) of the voltage across the sensing element is performed. The signal processing is then digitally done in real time. This processing mainly includes the digital quadrature demodulation, decimation and filtering. A description of the approach and its implementation for the GMI magnetic sensors are given. The system is fully programmable by software. This is why this approach is of great value for the automatic and real-time optimization of various physical parameters that impact the sensitivity and resolution of these sensors.