<![CDATA[Noise significantly limits the performance of capacitive MEMS accelerometers in high-precision sensing applications. This study investigates the effectiveness of Sigma-Delta Modulation (SDM) in reducing noise in a single-axis capacitive micro accelerometer (ADXL193) through systematic digital filter order optimization. The noise floor was measured under different SDM filter configurations to evaluate noise suppression characteristics, frequency rejection performance, settling time, and computational complexity. Experimental results demonstrate that SDM substantially reduces noise, particularly at power-line interference frequencies of 50 Hz and 60 Hz. Increasing the filter order enhances noise attenuation, achieving up to approximately 119 dB rejection for third-order filters, while simultaneously lowering the cutoff frequency. However, higher filter orders introduce longer settling times and increased computational demands. The findings reveal a clear trade-off between noise reduction performance and real-time system responsiveness. This study provides practical guidelines for selecting optimal filter orders in SDM-based MEMS accelerometer systems and highlights the potential of SDM techniques to significantly improve sensor signal quality for precision measurement applications.]]>
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