Design of Filter for Output Signals in Incremental Encoder for Detecting Speed and Position of Motors

The incremental encoder has been mostly used to measure the speed and position of the motor. As the output signals of encoder are high frequency digital signals, they have much influence on radiation noises due to switching of the power semiconductor circuits. It is so difficult to suppress the noises with the conventional LPF. In this paper, the hardware digital filter for suppressing noises in the output signals of the encoder signals is developed. As both the clock frequency and counter in the digital filter for encoder are easily adjusted according to the kinds of noises, any noises in the encoder can be entirely eliminated. The performance of the digital filter has been verified by simulation and experimental results.