The implementation of dual-truncation Sigma Delta D/A converters
The implementation of dual-truncation Sigma Delta D/A converters
复制标题
双截断Sigma Delta D/A转换器的实现
DOI：
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发表时间：
1992
期刊：
影响因子：
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通讯作者：
R. Schreier
中科院分区：
文献类型：
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作者：
X. Xu;G. Temes;R. Schreier
介绍了一种新颖的 D/A（数模）转换技术，该技术通过使用两个 D/A 转换器（DAC）实现高线性度和高分辨率 D/A 转换：一个具有高线性度但位分辨率较低，另一个具有低线性度但位分辨率相对较高。该技术的关键子系统是模拟微分器，它可以具有相对较大的增益误差，但只有非常小的相位误差。作者研究了与使用开关电容器电路实现这些微分器有关的问题。仿真结果表明，使用3级和33级DAC，系统在过采样比为128时达到了114dB的峰值SNR（信噪比）值。多位DAC的使用除了提高SNR之外，还减少了输入到模拟平滑滤波器的信号的摆幅，从而降低了该滤波器的非线性效应。<<ETX>>
A novel D/A (digital-to-analog) conversion technique is introduced which achieves high linearity and high resolution D/A conversion by using two D/A converters (DACs): one with high linearity but low bit resolution and the other with low linearity but relatively high bit resolution. The key subsystems in this technique are the analog differentiators, which can have relatively large gain error but only very small phase error. The authors examine the issues concerning the implementation of these differentiators with switched-capacitor circuits. Simulation results indicate that using a 3-level and a 33-level DAC, the system achieves a 114 dB peak SNR (signal-to-noise ratio) value when the oversampling ratio is 128. In addition to increasing the SNR, the use of a multibit DAC also reduces the swing of the input signal to the analog smoothing filter, and thus reduces the nonlinear effects of this filter.<<ETX>>