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Binary dithered oversampling analog to digital converter.

机译:二进制抖动过采样模数转换器。

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摘要

It is common knowledge among engineers that the best way to process analog signals would be in the digital domain. Signal processing varies from simple arithmetic operations such as adding multiple signals together to more complex operations such as implementing high order filters. Compared to analog, the digital domain presents a faster, more robust and more dynamic approach to handle signal processing. In order to perform digital processing on analog signals, these signals need to be properly converted into the digital domain with the best resolution as well as preserving the content of the signal with the least information loss.;Sigma Delta converters are the industry standards for high-resolution analog to digital converters (ADCs). To achieve this high resolution, the design requires high order integrators, multi-bit converters and complex digital filters. This results in a large size and power inefficient integrated circuit. This dissertation presents a novel analog to digital converter architecture that competes in terms of power, size and resolution with sigma delta converters. The theory behind this new architecture is deduced from half-toning in image processing. It captures the theory of error diffusion and blue noise masking used on multi-tone image processing and applies it in a similar fashion to digitize continuous analog signals.;Simulations have shown similar results for images half-toned through error diffusion and blue noise masking [17]. Moreover, there is a direct connection between error diffusion and sigma delta modulation, which inspired us to pursue the idea of developing a new ADC, the binary dithered oversampling ADC (BDO), based on blue noise dithering. We started with system level simulations to compare the performance of sigma delta to BDO and then developed proof of concept experiments to build the proper circuitry. It is important to mention that there has been a lot of work published about building simulation models to generate blue noise dither but there have not been a circuit developed to solely generate analog blue noise dither. It is true that a sigma delta modulator generates blue noise dither, but this is due to its negative feedback, which in return limits its speed. In this dissertation we are proposing a simple circuit, no negative feedback or integrators, that operates at much lower power and capable of achieving a bit resolution that is comparable to a first order sigma delta modulator.;Two generations of the BDO converter were implemented using 0.5 microm-CMOS technology to demonstrate their functionality. We also implemented a first order continuous time sigma delta modulator on the same integrated chip to compare both architectures. We compared both converters in terms of size, power, resolution and robustness. The proposed binary dithered oversampled converter was significantly smaller in size, consumed less power and achieved comparable resolution to that of the first order sigma delta modulator. In terms of robustness, sigma delta modulator can achieve higher resolution if we increase the oversampling ratio and use higher order integrators. The tradeoff here is an increase in size and power consumption in addition to facing some stability issues due to the high order integrators. On the other hand, the BDO converter can increase its resolution by optimizing some of its components, such as enhancing the high-pass filter responsible for the blue noise shaping, without radically increasing its size or power consumption.
机译:工程师之间的共同知识是,处理模拟信号的最佳方法是在数字领域。信号处理从简单的算术运算(例如将多个信号加在一起)到更复杂的运算(例如实现高阶滤波器)不同。与模拟相比,数字域提供了一种更快,更强大,更动态的方法来处理信号处理。为了对模拟信号进行数字处理,需要将这些信号正确地转换为具有最佳分辨率的数字域,并以最小的信息损失来保留信号的内容。Sigma Delta转换器是高标准的行业标准。分辨率的模数转换器(ADC)。为了实现这种高分辨率,设计需要高阶积分器,多位转换器和复杂的数字滤波器。这导致大尺寸和低功率的集成电路。本文提出了一种新颖的模数转换器架构,该架构在功耗,尺寸和分辨率方面都与sigma delta转换器竞争。这种新架构背后的理论是从图像处理的半色调推导出来的。它捕获了多色调图像处理中使用的误差扩散和蓝噪声掩蔽的理论,并以类似的方式将其应用于连续模拟信号的数字化。 17]。此外,误差扩散与sigma delta调制之间存在直接的联系,这激发了我们追求开发基于蓝噪声抖动的新型ADC(二进制抖动过采样ADC(BDO))的想法。我们从系统级仿真开始,以比较sigma delta与BDO的性能,然后开发了概念验证实验以构建适当的电路。值得一提的是,关于构建仿真模型以生成蓝噪声抖动的工作已经发表了很多,但是还没有开发出仅生成模拟蓝噪声抖动的电路。 sigma delta调制器确实会产生蓝噪声抖动,但这是由于它的负反馈,这反过来限制了它的速度。在这篇论文中,我们提出了一种简单的电路,没有负反馈或积分器,该电路以低得多的功率工作并且能够实现与一阶sigma delta调制器相当的位分辨率。 0.5微米CMOS技术演示其功能。我们还在同一集成芯片上实现了一阶连续时间西格玛德尔塔调制器,以比较两种架构。我们在尺寸,功率,分辨率和耐用性方面对这两种转换器进行了比较。所提出的二进制抖动过采样转换器的尺寸明显较小,功耗较小,并且分辨率与一阶sigma delta调制器相当。就鲁棒性而言,如果我们增加过采样率并使用更高阶的积分器,sigma delta调制器可以实现更高的分辨率。这里的权衡是由于高阶积分器还面临一些稳定性问题,同时还增加了尺寸和功耗。另一方面,BDO转换器可以通过优化其某些组件来提高其分辨率,例如增强负责蓝噪声整形的高通滤波器,而不会从根本上增加其尺寸或功耗。

著录项

  • 作者

    Helou, Jirar Nicolas.;

  • 作者单位

    University of Delaware.;

  • 授予单位 University of Delaware.;
  • 学科 Engineering Electronics and Electrical.
  • 学位 D.Eng.
  • 年度 2011
  • 页码 94 p.
  • 总页数 94
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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