Sigma Delta调制器系统结构及线性度优化技术研究

发布时间：2018-09-02 07:26

【摘要】：模数转换器(ADC)能将模拟域内的信号转换为数字域内的信号,是各种需要收集并处理模拟信号的系统中必不可少的重要部件。Sigma Delta ADC通过基于过采样和噪声整形技术,以其高精度的特点,在音频、先进传感器等方面有着广泛的研究和应用。在近年来的研究中,受线性度、分辨率、功耗、面积等指标的制衡,现阶段Sigma Delta ADC常通过优化调制器系统结构以及利用多比特量化来提高其精度及线性度。本文主要研究Sigma Delta调制器系统结构优化及提高线性度的技术。论文完成了对基于噪声耦合技术的Sigma Delta调制器的研究分析,对比了多种基于噪声耦合技术的调制器结构及其基本性能。运用MATLAB进行系统的行为建模及仿真,深入分析基于噪声耦合技术的Sigma Delta调制器在精度提升的同时,线性度提升的内在原因,同时进行了仿真与验证。多比特量化器的应用,带来了反馈DAC的非线性问题。这直接限制了Sigma Delta的谐波性能。如何在提高Sigma Delta系统线性度的同时减小额外资源消耗,成为研究的热点。本文设计了一种基于随机化原理的新型DWA算法,并对算法进行了系统的研究与仿真实现。利用MATLAB软件建模,仿真验证新型DWA算法对于调制器性能的提升作用,并与传统DWA算法进行对比。新型DWA算法电路由数字硬件语言VHDL设计实现,并在Quartus II软件的Modelsim进行了逻辑仿真验证。最后利用Design Compiler将RTL级代码综合成门级网表。综合后的新型DWA算法电路相比传统DWA算法在面积上下降8%,总动态功耗上下降13.9%。利用以上噪声耦合及新型DWA技术,完成了对整个Sigma Delta调制器的精度及线性度的提升,从系统层面上降低了Sigma Delta调制器的功耗及面积。
[Abstract]:Analog-to-digital converter (ADC) can convert signals from analog domain to digital domain. It is an essential component of various systems that need to collect and process analog signals. Sigma Delta ADC is based on over-sampling and noise shaping technology. Because of its high accuracy, it has been widely studied and applied in audio frequency, advanced sensors and so on. In recent years, due to the check and balance of linearity, resolution, power consumption, area and so on, Sigma Delta ADC usually improves its precision and linearity by optimizing the structure of modulator system and using multi-bit quantization. This paper focuses on the optimization of Sigma Delta modulator system structure and the improvement of linearity. In this paper, the research and analysis of Sigma Delta modulator based on noise-coupling technology are completed, and the structure and basic performance of various modulators based on noise-coupled technology are compared. The behavior modeling and simulation of the system based on MATLAB are carried out, and the inherent reasons of the linearity enhancement of the Sigma Delta modulator based on the noise coupling technology are deeply analyzed, and the simulation and verification are carried out at the same time. The application of multibit quantizer brings the nonlinear problem of feedback DAC. This directly limits the harmonic performance of Sigma Delta. How to improve the linearity of Sigma Delta systems and reduce the consumption of additional resources has become a hot research topic. In this paper, a novel DWA algorithm based on randomization principle is designed, and the algorithm is systematically studied and simulated. MATLAB software is used to model and simulate the new DWA algorithm to improve the performance of modulator, and compared with the traditional DWA algorithm. The new DWA algorithm circuit is designed and implemented by digital hardware language VHDL, and the logic simulation is carried out in Modelsim of Quartus II software. Finally, the RTL level code is synthesized into gate network table by Design Compiler. Compared with the traditional DWA algorithm, the new DWA algorithm circuit is reduced by 8 points in area and 13.9 in total dynamic power consumption. Using the above noise coupling and new DWA technology, the accuracy and linearity of the whole Sigma Delta modulator are improved, and the power consumption and area of the Sigma Delta modulator are reduced from the system level.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN761

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