Accuracy Improvement of Rotational Speed Sensors by Novel Signal Processing Method

A novel signal processing method is proposed for determining the rotational speed more accurately. In this method, the periodic output signal of a rotational speed sensor is filtered and then sampled in a defined time window. The sampled discrete signal is further filtered to improve its Signal-to-Noise Ratio (SNR). The rotational speed is derived by a precise determination of the signal frequency of the periodic signal under using Discrete Fourier Series (DFS) and iterative Self-Correction and optimization algorithms. From the experimental results, an accuracy of about 0.2% can be achieved. This method can be used in all kinds of rotational speed sensors and encoders with analogue signal output.