<abstract xmlns="http://www.w3.org/1999/xhtml"><p>Optical rotary encoders generate nonlinear sine and cosine signals in response to a change of angular position that is being measured. Due to the nonlinear shape of encoder output signals, encoder sensitivity to very small changes of angular position is low, causing a poor measurement accuracy level. To improve the optical encoder sensitivity and to increase its accuracy, an improved linearization circuit based on pseudo-linear signal generation and its further linearization with the two-stage piecewise linear analog-to-digital converter is presented in this paper. The proposed linearization circuit is composed of a mixed-signal circuit, which generates analog pseudo-linear signal and determines the first four bits of the final digital result, and the two-stage piecewise linear analog-to-digital converter, which performs simultaneous linearization and digitalization of the pseudo-linear signal. As a result, the maximal value of the absolute measurement error equals to 3.77168·10<sup>−5</sup> [rad] (0.00216°) over the full measurement range of 2π [rad].</p></abstract>

Optical rotary encoders generate nonlinear sine and cosine signals in response to a change of angular position that is being measured. Due to the nonlinear shape of encoder output signals, encoder sensitivity to very small changes of angular position is low, causing a poor measurement accuracy level. To improve the optical encoder sensitivity and to increase its accuracy, an improved linearization circuit based on pseudo-linear signal generation and its further linearization with the two-stage piecewise linear analog-to-digital converter is presented in this paper. The proposed linearization circuit is composed of a mixed-signal circuit, which generates analog pseudo-linear signal and determines the first four bits of the final digital result, and the two-stage piecewise linear analog-to-digital converter, which performs simultaneous linearization and digitalization of the pseudo-linear signal. As a result, the maximal value of the absolute measurement error equals to 3.77168·10−5 [rad] (0.00216°) over the full measurement range of 2π [rad].

An Improved Linearization Circuit Used for Optical Rotary Encoders

Department of Measurements, Faculty of Electronic Engineering

Department of Electronics, Faculty of Electronic Engineering

Measurement Science Review

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

{"article-title":"An Improved Linearization Circuit Used for Optical Rotary Encoders"}

Optical rotary encoders generate nonlinear sine and cosine signals in response to a change of angular position that is being measured. Due to the nonlinear...

An Improved Linearization Circuit Used for Optical Rotary Encoders

Published Online: Oct 23, 2017

Page range: 241 - 249

Received: Jun 07, 2017

Accepted: Oct 10, 2017

DOI: https://doi.org/10.1515/msr-2017-0029

Keywords
Angular position measurement, linearization, analog-to-digital conversion, accuracy improvement

© 2017 Jelena Jovanović et al., published by De Gruyter Open

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

An Improved Linearization Circuit Used for Optical Rotary Encoders

Published Online: Oct 23, 2017

Page range: 241 - 249

Received: Jun 07, 2017

Accepted: Oct 10, 2017

DOI: https://doi.org/10.1515/msr-2017-0029

KeywordsAngular position measurement, linearization, analog-to-digital conversion, accuracy improvement

© 2017 Jelena Jovanović et al., published by De Gruyter Open

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
Angular position measurement, linearization, analog-to-digital conversion, accuracy improvement