| Summary: | 碩士 === 國立交通大學 === 電機與控制工程系所 === 96 === This paper presents a Sigma-Delta ADC which can change resolutions when the type of the input signal is different. This ADC provides two modes. One is designed for bio-electric signals; the other is designed for bio-image signals. This ADC can change its resolution by the control unit of a multi-channel design for bio-electric and bio-image signal through SPI. It includes two parts: Sigma-Delta modulator and decimation filter.
The proposed ADC operates at 1.28 MHz. Sampling rate is 640 kHz. For bio-electric signals, oversampling rate (OSR) is 256; for bio-image signals, OSR is 32. The ADC communicates with DSP or other devices by SPI bus. In the bio-electric signal mode, SNR is 50dB, effective number of bits (ENOB) is 10-bit; in the bio-image signal mode SNR is 50dB, ENOB is 8-bit. It has been fabricated by TSMC 0.18 �慆 CMOS 1P6M standard process. The total power consumption of the chip is about 14.4 mW under 1.5V supply, and the power consumption of Sigma-Delta modulator is about 0.98 mW; the power consumption of digital part is 13.3 mW. The area of the chip is 3.21 mm2.
|
|---|
