The parameters of the analog waveforms produced by front-end electronics of absolute optical encoders are affected by substantial differences and drifts. Te threshold level required to convert the generated analog signal into a digital square wave in each read-out channel, has therefore to be calibrated so as to keep the output duty-cycle close to its ideal valute of 50%. This paper presents a digital self-calibration circuit specifically designed for this purpose. The circuit performs dynamic calculation fo the threshold level, continuously compensating for encoder non-idealities while the system is normally operating. This avoids the need for manual calibration, provides thermal stabilization, and prevents performance degradation. The proposed digital calibration system was integrated in conventional CMOS technology and was then successfully evaluated
A Digital Self-Calibration Circuit for Absolute Optical Rotary Encoders
Gottardi, Massimo;
2003-01-01
Abstract
The parameters of the analog waveforms produced by front-end electronics of absolute optical encoders are affected by substantial differences and drifts. Te threshold level required to convert the generated analog signal into a digital square wave in each read-out channel, has therefore to be calibrated so as to keep the output duty-cycle close to its ideal valute of 50%. This paper presents a digital self-calibration circuit specifically designed for this purpose. The circuit performs dynamic calculation fo the threshold level, continuously compensating for encoder non-idealities while the system is normally operating. This avoids the need for manual calibration, provides thermal stabilization, and prevents performance degradation. The proposed digital calibration system was integrated in conventional CMOS technology and was then successfully evaluatedI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
