High-Resolution ADCs for Biomedical Imaging Systems

With the rapid development of biomedical imaging systems, the requirement of the accuracy of an Analog-to-Digital Converter (ADC) becomes more and more critical. Traditional Nyquist-rate analog to digital data converters cannot meet the requirement any more. Sigma-Delta analog to digital data converter, which makes a trade-off between speed and accuracy, can achieve an ideal accuracy by employing the oversampling and noise-shaping technology. In this work, a Verilog-AMS model for sigma-delta modulator is built, including the topologic, the order of stage, oversampling rate, system parameters, etc. On the basic of theoretical analysis and scientific flow path, finally, a third-order 1-bit sigma-delta modulator is designed and optimized, whose performance agrees well with the theoretical module