The Development of Magnetic Rotary Encoder System Based on High Resistivity MR Film Sensor for Automobile Speed-measuring

To meet the need of automobile industry, a new kind of high resistivity MR (magneto resistance) film sensor with NiFeCr seed layer has been made. The magnetic rotary encoder system based on the sensor is designed. The system consists of the magnetic drum, magnetic head, amplification and shape circuit, quadruplicated frequency circuit, measure and display unit, etc. The characteristics of this system include simple structure, anti-adverse circumstance, fast response speed, low cost and high reliability. The system fits especially to automobile speed measuring.