逐次逼近A／D变换器和D／A变换器

逐次逼近Ａ／Ｄ变换器和Ｄ／Ａ变换器洪志良（复旦大学电子工程系，上海，２００４３３）ｌ引言逐次逼近Ａ／Ｄ变换器是最早采用的Ａ／Ｄ变换技术，由于它对工艺技术的要求不苛刻，使用硬件少，早期就被用于较高精度Ａ／Ｄ变换器的集成中。逐次近似Ａ／Ｄ变换不用额外的工...     

一比特过取样A／D, D／A变换系统分析

一比特过取样Ａ／Ｄ，Ｄ／Ａ变换系统和多比特Ａ／Ｄ，Ｄ／Ａ变换系统相比较而言，有着独特的优越性。本文分析了仍存在的问题，并在原有的研究基础上继续分析了各种结构的一比特过取样Ａ／Ｄ，Ｄ／Ａ变换系统的输出波形和频谱。     

过取样△∑调制技术（一）──过取样AD／DA变换的基本概念──

过取样ＡＤ／ＤＡ变换（ｏｖｅｒｓａｍｐｌｅｄＡＤ／ＤＡＣｏｎｖｅｒｔｅｒ）作为一种电路设计技术，已经迎来了一个新的发展时期，该技术使用了△调制和△∑调制这些过去大家都很熟悉的优选电路，本文将说明这一新变换技术的原理，传统的ＡＤ／ＤＡ变换的极限范围，及它对大规模ＬＳＩ设计的影响。过取样方式增加了数字处理的比重，减轻了模拟电路的负担，适应了ＶＬＳＩ发展的要求。     

真RMS—DC变换器AD736／AD737

ＡＤ７３６／ＡＤ７３７是ＡＤ公司推出的真有效值直流变换器。和以往的有效值测量技术不同，真有效值直流变换可以直接测得各种波形的真实有效值，它不是采用整流加平均的测量技术，而是采用信号平方后积分的平均技术。采用ＡＤ７３６／ＡＤ７３７可以简化仪器的设计，增加信号测量品种，并且灵敏度、精确度也大大改善。本文讨论了真ＲＭＳ测量技术的工作原理，并给出了ＡＤ７３６／ＡＤ７３７的典型应用电路。     

过取样△∑调制技术（一）：—过取样AB／DA变换的基本概念

过取样ＡＤ／ＤＡ变换作为一种电路设计技术，已经迎来了一个新的发展时期，该技术使用了△调制和△∑调制这些过去大家都很熟悉的优选电路，本文将说明这一新变换技术的原理，传统的ＡＤ／ＤＡ变的极限范围，及它对大规模ＬＳＩ设计的影响。过取样方式增加了数字处理的比重，减轻了模拟电路的负担，适应了ＶＬＳＩ发展的要求     

能够同时进行4个通道的A—D变换的音频LSI

新加坡ＴｒｉＴｅｃｈＭｉｃｒｏｅｌｅｃｔｒｏｎｉｃｓ公司开发出了能够同时对４个通道的音频信号进行Ａ－Ｄ变换的Ａ—Ｄ／Ｄ－Ａ变换ＬＳＩ－ＴＲ２８６４０。Ｄ－Ａ变换电路的输出通道有６个,可用于具有多通道音频再生功能的ＡＶ设备及汽车音响等。Ａ－Ｄ／Ｄ－Ａ变换电路为西Ｚ型,分辨率和取样频率得最大值分别为２４比特和９６ｋＨＺ。模拟信号的标准输入输出电压范围为３．０Ｖｐｐ。Ａ－Ｄ变换电路的动态范围和Ｓ／Ｎ的标准值均为１００ｄＢ,ＴＨＤ＋Ｎ（总谐波失真与噪声之和）的标准值为－９０ｄＢ,最大过取样比为６４。Ｄ－…     

混合集成A／D变换器——B—MSZD

本文阐述了军用高速低功耗Ａ／Ｄ变速器的设计与研制。Ｂ－ＭＳＺＤ Ａ／Ｄ变换器具有集成度高、体积小、重量轻、功耗低、功能齐全等特性。     

数字相机用CCD信号处理器

ＣＣＤ（电荷耦合器件）信号处理器ＶＳＤ２１００是一款完整的数字相机ＩＣ,它为ＣＣＤ阵列输出提供信号调理和１０位Ａ／Ｄ变换。它所提供的ＣＣＤ信号处理包括：从像素获取视频信息的相关双取样（ＣＤＳ）;与供变化的照明度条件用的数字控制相当的０ｄＢ到＋３４ｄＢ增益;为得到精确黑色基准的黑色电平箝位。该信号处理器的特性包括５３ｄＢＳＮＲ。其１０位Ａ／Ｄ变换的变换率达２７ＭＨｚ,而且没有漏代码。低电压（２．７Ｖ到３．６Ｖ）,低功率（２．７Ｖ为１６０ｍＷ,３．０Ｖ为１９０ｍＷ）便携工作。它的应用包括：视频相机,…     

过采样技术及其应用

本文讨论ＰＣＭ信号的量化噪声并用过采样与噪声整形技术来改进数字信号的信噪比，给出了一些应用例子，例如，低比特过采样Ａ／Ｄ与Ｄ／Ａ变换，１比特ＡＤＣ，ＭＡＳＨ和数字扬声器。     

过采样∑－△A／D调制器

过采样∑－△Ａ／Ｄ调制器洪志良（复旦大学电子工程系，上海，２００４３３）１引言过采样∑－△Ａ／Ｄ变换器通过过采样以时间来交换精度，从而避免实现高精度Ａ／Ｄ变换器所需要的复杂性。∑－△调制器结构是迄今为止在数字ＶＬＳＩ技术中执行高精度Ａ／Ｄ变换最吸引人...     

High accuracy pipeline D/A convertor configuration

A new pipeline D/A convertor configuration is presented. This structure can be used as a module in a pipeline A/D convertor. The advantage of this D/A structure is that the accuracy is not influenced by any stray capacitor such as bottom plates or drain/source junction capacitors. As a result video frequency operation can be obtained with this structure     

一种基于流水逐次逼近比较方式的模／数转换器

提出了一种新型模数转换方法——流水逐次逼近比较式模数转换法,并给出了相应的实验结果。在达到逐次逼近比较A/D转换器的相同转换时间tc的前提下,流水逐次逼近比较式A/D转换器的m和n函数关系等同于逐次逼近比较A/D转换器,而其tc和n的函数关系优于逐次逼近比较A/D转换器,并且比较流水式A/D转换器易于实现。     

New analogue multiplier-divider circuit based on cyclic data convertors

A new method for the realisation of analogue multiplier/divider circuits is presented. The method uses a modified cyclic data convertor that operates sequentially as an A/D convertor and as a D/A multiplying convertor in such a way that it performs the analogue operation v/sub 0/=v/sub x/v/sub y//v/sub z/.<>     

Dynamic element matching for high-accuracy monolithic D/A converters

A novel way to obtain a very high accuracy in the bit weighting required for bipolar monolithic digital-to-analog (D/A) converters is described. The new method combines passive division using matched elements with a time division concept, needs no trimming, and is insensitive to element aging. A 12-bit monolithic D/A network with internal reference sources, built as a test circuit, demonstrates the versatility of this new technique.     

基于AD650的VFC型A/D转换器

针对实际工程的技术要求，设计了一种新型高精度模数转换电路——VFC型A／D转换器。该电路作为计算机控制系统与受控设备之间的接口电路，在计算机控制下，所有的逻辑判断和校正网络均由计算机软件实现，此转换电路不仅调试方便、简单，而且增加了系统的可靠性。实践表明，设计的VFC型A／D转换电路完全满足系统设计要求。本文详细叙述了VFC型A／D转换电路的工作原理、设计思想和实现方法。     

Proposal and implementation of a new interpolation technique for a double folding A/D converter

This proposal of a new interpolation technique is presented for application in a double folding A/D converter with interpolation. This interpolation technique is applied in the master latches of the A/D converter without consumption increase. Compared to resistive interpolation, this new interpolation technique has the advantage of avoiding the resistive interpolation ladder adding only three transistors in some master latches and the current is the same as in the simple master latch. A 6-bit A/D converter was designed and implemented in a 1.2 μm BiCMOS process, an F_T of 8 GHz, to explain the implementation of interpolation circuitry and evaluate the experimental results.     

A monolithic charge-balancing successive approximation A/D technique

A new multiple-differential-voltage input, MOS, sampled-data, `charge-balance' comparator which can `weight' or scale each of many input voltage pairs has been developed. This comparator easily allows a differential analog input voltage capability on a monolithic A/D converter and greatly reduces the required number of resistors and decoding switches of a potentiometric successive approximation register (SAR) A/D design. An 8 bit converter has been built which uses 20 Rs and 32 switches as compared to the 256 Rs and 512 switches of a standard 2/SUP N/R ladder design. Measurements made on the 8 bit A/D converter are reported and indicate that at least 12 bit converters are possible with this technique. Therefore, a 13 bit converter has been designed which exhibits even greater component reductions-33 Rs and 64 switches instead of 8192 Rs and 16384 switches. A simple interface to microprocessors is provided for both converters which makes use of the standard logic signals of the control bus where the A/D is designed to appear as memory or an I/O port to the microprocessor. A new flexible reference voltage circuit is presented which, in combination with the analog differential input voltage feature, can accommodate arbitrary analog input voltage spans with any desired zero scale offset.     

光A／D转换

高速A／D转换是雷达、声纳、电子战、飞行器导航及身份识别等国防领域中的关键技术。用超高速光脉处理微波信号是实现对超宽带信号A／D转换的一种新的手段,本文讨论了光子A／D转换的几种方法,并分析了取样脉冲质量对转换精度的影响。     

Time-interleaved oversampling convertors

A new architecture is proposed which exploits the time-interleaving concept to increase the oversampling ratio in delta-sigma modulators. It is shown that the effective oversampling ratio is increased by a factor M through the use of M interconnected modulators. Although a high speed sample-and-hold circuit is still required for an analogue-to-digital convertor, speed constraints are significantly reduced for the majority of analogue parts such as loop filters, A/D and D/A blocks.<>     

新型自控原理实验装置的研制

本文介绍了一种基于计算机并口A/D、D/A转换实现的新型自控原理实验装置。该装置由计算机、A/D及D/A接口板、模拟实验箱等组成，软件在Windows环境下用VB编制，实现了对实验数据的采集、存储和计算处理，使实验结果更准确直观，显著提高了实验效果。