Chopper-Stabilized Continuous-time Sigma-Delta Modulator Design for Biomedical Sensing Applications
| Autor: | Ya-Wen Kuo, 郭雅雯 |
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| Rok vydání: | 2012 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 100 Continuous-time sigma-delta modulators play an important role in the development of biomedical sensors. It is suitable for monitoring of basic human vital functions (i.e., heartbeat and respiration). However, the physiological signal is very weak and it belongs to low-frequency range, the observed signals are strongly inter¬fered by the intrinsic flicker noise form CMOS transistors, which will cause a certain degree of difficulty in the identification. This thesis describes the implementation of loop filter using a differential chopper-stabilized configuration to reduce the influence of flicker noise on sigma-delta modulator within the signal bandwidth. The noise analysis of this sigma-delta modulator is calculated by the time-domain noise simulation. This method can take the noise factors into account when analyzing the overall performance. The proposed sigma-delta modulator is fabricated using TSMC 0.35μm 2P4M CMOS technology. The chip area is 1.403 x 1.4 mm2. With a sampling rate of 20.8 kHz, the modulator achieves 84.4 dB of the peak SNDR and ENOB is 13.7-bit within signal band¬width of 10Hz. It dissipates 3.46 mW under 3V supply voltage. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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