Linearization signal conditioning circuit for tri-axial micro-grating MOEMS accelerometer

Abstract

This paper proposes what we believe to be a novel linearization signal conditioning circuit for a tri-axial micro-grating micro-opto-electro-mechanical systems (MOEMS) accelerometer. The output of a micro-grating accelerometer varies as a sine/cosine function of the acceleration. The proposed circuit utilizes a subdivision interpolation technique to process these nonlinear intensity variations and render a linear digital output across the full range. Such a linearization circuit was achieved through a 90-degree phase-shift circuit, high-precision DC bias-voltage and subdivision interpolation circuits to reduce the influence of phase, magnitude, and offset errors of the sine-cosine signals on the interpolation factor, improving the resolution and accuracy of acceleration detection. Experimental results demonstrated that the micro-grating MOEMS accelerometer achieves a resolution of sub-mg, cross-axis errors of 3.57%, 1.22% and 0.89% for x-, y- and z-aixs, respectively. The bias instabilities and velocity random walks for the vertical and lateral accelerometer are superior to 26 µg and 38.7 µg/√Hz. The tri-axial micro-grating MOEMS accelerometer exhibits significant potential for applications requiring high sensitivity and large operation ranges, including the automotive industry and military equipment.