Abstract
The detection resolution of a giant magneto-impedance (GMI) sensor is mainly limited by its equivalent input magnetic noise. The noise characteristics of a GMI sensor are evaluated by noise modeling and simulation, which can further optimize the circuit design. This paper first analyzes the noise source of the GMI sensor. It discusses the noise model of the circuit, the output sensitivity model and the modeling process of equivalent input magnetic noise. The noise characteristics of three modules that have the greatest impact on the output noise are then simulated. Finally, the simulation results are verified by experiments. By comparing the simulated noise spectrum curve and the experimental noise spectrum curve, it is demonstrated that the preamplifier and the multiplier contribute the most to the output white noise, and the low-pass filter plays a major role in the output 1/f noise. These modules should be given priority in the optimization of the noise of the conditioning circuit. The above results provide technical support for the practical application of low-noise GMI magnetometers.
Highlights
Since the discovery of the giant magneto-impedance (GMI) effect in the CoFeSiB soft magnetic material by the Mohri team in Japan in 1992, the GMI effect has been found in many soft magnetic materials [1,2]
1/f noise thesensor, GMI the sensor, the conditioning circuit isstructure divided is into two parts: the excitation circuit and the detection circuit
= 5.52 × 10−5 V/√Hz, according to the contribution of each module to the total output voltage noise spectral density, it is not difficult to find that the D and E modules are the main source of output noise in the range of white noise, and the F module is the main source of output noise in the range of 1/f noise
Summary
Since the discovery of the giant magneto-impedance (GMI) effect in the CoFeSiB soft magnetic material by the Mohri team in Japan in 1992, the GMI effect has been found in many soft magnetic materials [1,2]. According to previous research results, the noise of a GMI sensor mainly comes from three sources: GMI component intrinsic noise, conditioning circuit noise and external interference noise [9]. The intrinsic noise of GMI components is the effect of multiple noise sources. In the low frequencies (less than 1 kHz), the thermomagnetic noise caused by the thermal fluctuation of magnetization contributes significantly to the intrinsic noise of the GMI. The intrinsic noise of conditioning the GMI component is 2~3 noise of thethrough. 1/f noise thesensor, GMI the sensor, the conditioning circuit isstructure divided is into two parts: the excitation circuit and the detection circuit. MATLAB, dominant noise source found, allowing further optimization of the dominant noise improving the noise characteristics of the conditioning circuit. Source and significantly improving the noise characteristics of the conditioning circuit.
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