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 0.35£gm 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.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0712112-150713 |
| Date | 12 July 2012 |
| Creators | Kuo, Ya-Wen |
| Contributors | Chia-Hsiung Kao, Jyi-Tsong Lin, Ko-Chi Kuo, Tzyy-Sheng Horng |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0712112-150713 |
| Rights | user_define, Copyright information available at source archive |
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