A full sample-type magneto-impedance (MI) magnetometer with programmable circuit for high compatibility

In this study, a programmable Magneto-Impedance (MI) sensor circuit has been designed by using a Field-Programmable-Gate-Arrays (FPGA), and an operational amplifier integrator has been used to replace the peak hold circuit in the conventional system to sample the entire output of the sensor. Since there is no need to adjust the sampling timing to match different MI sensor’s outputs, it is more suitable for mass production than conventional circuits. It was also found that the output of the sensor has the same sensitivity on the rising and falling edges of the excitation current. The output of two parts of the sensor is sampled by an asynchronous sampling frequency, and the noise level of the system proposed is reduced. In comparison with the conventional system, the proposed system in this work has higher sensitivity and lower noise level when utilizing the same sensor, so it might be applied to the bio-medical signal measurement in the future.