Research on Improving Low Speed Property of Tachometer Based on Electro-Optical Encoder

Incremental encoder combined with M/T method is the most popular and more appropriate digital tachometer. But if the speed is low or ultra-low, there will be several questions, such as low precision, bad timeliness, the jitter caused by Machine vibration. Aiming at resolving these questions, this paper respectively proposes an eliminate-jitter method based on FPGA, an enhanced method timeliness based on extrapolation method and an enhanced M/T method to expand speed range. These methods improve the performance of the encoder at low speed, and make use of encoder in research and practice better.