二阶多比特Sigma-Delta ADC中的自适应量化算法  

Adaptive Quantization Algorithm of Second-Order Sigma-Delta ADC with Multibit Quantizer

作　　者：褚炜路[1] 戎蒙恬[1] 李萍[1] 刘文江[1] 

机构地区：[1]上海交通大学电子工程系,上海200240

出　　处：《上海交通大学学报》2008年第2期308-311,316,共5页Journal of Shanghai Jiaotong University

基　　金：国家自然科学基金委创新研究群体基金(编号60521002);上海-应用材料研究与发展基金(0501)和(06SA09)资助项目

摘　　要：针对二阶多比特Sigma-Delta ADC的量化电平对信噪比的影响,提出了自适应量化算法(AQ).该算法可根据输入信号的幅度变化,动态地调节多比特ADC的参考电平,从而改善二阶多比特Sigma-Delta ADC在小幅度输入时信噪比下降的问题.在此基础上,运用动态电阻匹配的方法,进一步减小了由于反馈数字模拟转化器(DAC)电阻不匹配带来的非线性噪声.仿真结果验证了该算法的有效性.Aiming at the effect caused by reference voltage of the quantizer upon the value of SNR in the 2nd order multi-bit sigma-delta ADC, this paper put forward an adaptive quantization algorithm. According to the amplitude of the input signal, the quantizer will adjust the reference voltage of the multi-bit quantizer in order to improve the SNR decreasing problem when the input amplitude is relatively low. Based on this method, dynamical resistor matching was used to reduce the non-linear noise caused by the unmatching of the feedback DAC. The simulation result shows the validity of this algorithm.

关 键 词：多比特量化 信噪比 自适应量化 动态电阻匹配 

分 类 号：TN79[电子电信—电路与系统]