Excitation method and device for a giant magneto-impedance sensor

Abstract

The invention discloses a multi-frequency excitation method and device of a giant magneto-impedance sensor. The multi-frequency excitation generation method includes the following steps that: frequency divided filtering and frequency mixing processing is performed on oscillation signals which generate excitation signals, so that five kinds of excitation signals with different frequencies can be generated; and one kind of excitation signals from the five kinds of excitation signals is adopted as excitation signals. The device for realizing multi-frequency excitation includes an oscillation circuit, a frequency divided filtering circuit, a frequency mixing circuit, a multi-way switch circuit, a microprocessor and a comparison circuit. The excitation method and device provided by the invention have universality. With the time division multi-frequency excitation method adopted, the sensitivity of the giant magneto-impedance sensor can be improved effectively.

Description

Technical field [0001] The invention relates to an excitation method and device of a sensor, in particular to an excitation method and device of a giant magnetic impedance sensor. Background technique [0002] The magneto-impedance effect was first discovered in 1935, but due to the limitations of materials and environment, this discovery did not cause widespread concern. Until 1992, K. Mohri and others of Nagoya University in Japan discovered the giant magneto-impedance (GMI) effect in CoFeSiB amorphous wire materials, that is, the AC impedance of magnetic materials changes significantly with the change of the applied DC magnetic field. This change It is an order of magnitude higher than the GMR effect, which has attracted widespread attention. The current more consistent definition of the giant magneto-impedance effect is: the giant magneto-impedance effect refers to the effect that the AC impedance of a magnetic material changes significantly with the change of an external DC...

AI Technical Summary

Problems solved by technology

In the approximately linear region of the curve, a large giant magnetoimpedance effect can be obtained without a large excitation frequency, that is, the sensitivity is high; when the excitation frequency is high, the change range of the impedance change rate is small, and the sensitivity is low

[0018] (5) When the excitation frequency is fixed, the sensitivity that can be achieved is different for different magnetic field variation ranges

[0019] Sensitivity and range are the two most important indicators in the design of giant magneto-impedance sensors, but it can be seen from the above analysis that the traditional single-frequency excitation method is difficult to meet the requirements of these two aspects at the same time

Although the single-frequency excitation method is simple, it has certain limitations. Improving the excitation method is an important way to improve the performance of giant magneto-impedance sensors.

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