In speed analysis and measurement, especially for non-contact rotation and displacement signals, eddy current velocimeter can continuously and accurately collect various parameters of trajectory motion such as vibration and rotation. The industrial background of this sensor application is that it can directly and non-contact measure the state of rotating shaft, such as early judgment of mechanical problems such as rotor imbalance, misalignment, bearing wear, shaft crack and friction, which can provide key information. Eddy current speed sensor is widely used in industry because of its long-term reliability, wide range, high sensitivity, high resolution, fast response and strong anti-interference ability. Eddy current velocity sensor is widely used in industrial basic research, precision equipment manufacturing and equipment testing. Specifically, the current eddy current speed sensor is mainly used to study and measure the trajectory data of high-speed rotating machinery and reciprocating machinery, as well as vibration.