A subdivision method for improving resolution of analog encoders

The objective of this paper is to improve the resolution of incremental analog encoders. In practice, the outputs of analog encoders are not the quadrature sinusoidal waves, in which there always are mean offsets, phase offsets, and amplitude distortion. In this paper, to calibrate these encoders, the calibration coefficients are introduced. These coefficients are obtained by the least-squares method to attenuate offsets and distortion of encoder outputs. MATLAB/Simulink are used to simulate the algorithm of signal calibration and a subdivision algorithm is given to improve the resolution of analog encoders. In the experiments, the algorithms are implemented and tested on the digital signal processor in a motor driver. Finally, through a servo motor driver, the motor can be controlled and performs well by using an analog encoder with feedback from subdivided signals.