D／A转换器叠加提高分辨率方法研究

通过对两片D／A转换器叠加使用效果的研究，介绍一种采用低分辨率DA转换器构成高分辨率DA转换器的方法。     

A Study of High-Precision CNC Lathe Thermal Errors and Compensation

This study is addressed at the thermal deformation errors resulting from temperature rise that contribute to 40%–70% of the precision errors in machining at a turning centre, and proposes an economic, accurate, and quick measurement method. It also investigates the thermal error differentials between static idle turning and in the actual cutting environment. The temperature measurement units are intelligent IC temperature sensors with correction circuits. The A/D card extracts and transforms data and saves data in the computer files, and the displacement sensor measures the displacement deviation online during cutting. The temperatures and the deviation of thermal drifts so obtained are used to establish the relationship function using multivariable linear regression and nonlinear exponential regression models, respectively. Finally, this paper compares software compensation methods for the thermal-drift relationship. As proven by experiments, the software compensation method can limit the thermal error of a turning centre to within 5 μm. Moreover, the software compensation for the thermal error relationship using a single variable nonlinear exponent regression model can reduce the error by 40% to 60%.     

一种A/D转换器静态参数的低成本测试方法

在IC产业链中，测试是必不可少的环节之一，而如何降低过高的测试成本也逐渐成为研究的热点。本文基于伺服环方法和权位点测试法提出了一种A／D转换器静态参数的低成本测试方法，并在自主开发的JC-3196A集成电路测试系统上实现。该方法具有普遍的适用性，对降低数模混合信号集成电路的测试成本具有重要意义。     

A new method for integrating analog to digital conversion based on error reduction

This paper presents a method for eliminating errors of electronic components in integrating analog to digital converters. Offset error in integrator, comparator and amplifiers of dual-slope converter is a great limitation for increasing the resolution of this type of analog to digital converter. The paper proposes an idea that effectively eliminates offset error of integrator and reduces errors of other components. To validate the efficiency of the proposed method, simulation and experimental results are represented in this paper. As a result, this method can potentially allow a cost-effective design of high-resolution ADCs with low performance Op-Amps.     

Increasing of accuracy of angular measurements by using hybrid photoelectric converters

The basis sources and methods of reducing the errors of incremental photoelectric digital converters for angular measurements are analyzed. A method of constructing hybrid photoelectric converters that increase the accuracy of angular measurements is proposed. The result is achieved by simultaneous measurements of the turning angle and current radial deflections of the converter shaft axis.     

车用大功率两相Boost变换器耦合电感设计

大功率DC／DC变换器中交错并联技术被广泛使用。为了减小变换器的体积,将耦合电感引入大功率DC／DC变换器。首先介绍了相关理论,其次给出了耦合电感的设计步骤和公式,最后给出了有限元分析（finiteelementanalysis,FEA）仿真数据。将耦合电感和传统的单路分立电感进行了比较。仿真结果表明,给出的设计方法可行,可以大大减小变换器的体积。     

流水线模数转换器的接口技术

介绍了基于流水线结构的模数转换器的基本结构及原理，并在此基础上给出了流水线型AD转换器的接口电路．能很好地匹配AD转换器的性能。消除转换时产生的误差和干扰。     

A survey on the dynamic characterization of A/D converters

This article presents the different ways used to characterize A/D converters through the “CanTest System” test bench and its functionalities. The different ways used to characterize A/D converters dynamically could be organized into three parts: time domain, statistical and spectral analysis. The most commonly used algorithms in time domain analysis are presented. Due to instrumentation error, some may give “inaccurate” results. We explain why and propose a new method based on a direct estimation of conversion noise to avoid this problem. The different methods and applications linked to statistical analysis are also described. We explain the three different methods used to measure the differential non-linearity (DNL) and the integral non-linearity (INL). A comparison between these three algorithms in simulation and through an experimental case shows that their behaviours differ when the histogram presents edging effects. The final study presented in this paper concerns the A/D converter performance evaluation by analysis in frequency domain. From the output power spectrum, relationships are given for the computation of all spectral parameters. We present a correction to include in the computation of spectral parameters when the analog input does not span the entire full-scale range of the A/D converter under test. When the input generator provides a sine wave with harmonics, we propose the “Dual-Tone” method in order to separate the distortion associated with the component and the one associated with the generator. In the last part of this paper, we describe the test bench giving its specifications (acquisition system, frequency range,…). Some typical measurements and comments about the interest of analysis in different modes are given also.     

液晶显示器的多极驱动方式

本文阐述了液晶显示器(LCD)的主要技术特性与驱动方法,重点论述了LCD的多极驱动方式,并结合一种以三极方式驱动LCD的单片4(1/2)位A/D转换器,讨论了三级驱动方式在该A/D转换器中的应用     

ICL7135在智能仪表中的应用

介绍一种双积分A／D转换器ICL7135与单片机89c52的简单接口，并基于这种用法提出了一种自校正算法，给出了应用电路和部分程序代码。     

基于贝努力映射和CPLD的混沌A/D转换器

本文分析了基于贝努力映射的混沌A／D转换器的工作原理，给出了初值计算方法。设计了仿真电路，分析了理想参数情况下，该混沌A／D转换器的误差。采用CPLD设计了实验电路，分析了实验电路的转换误差，指明了改进混沌A／D转换器性能的方向。为混沌A／D转换器的理论研究和实用化进行了有益探索。     

箝位型多电平逆变器的仿真研究

研究了1种新型箝位型多电平逆变器拓扑。介绍了1种适用于n电平的非常有效的非正交坐标变换SVM算法并以永磁同步电机为负载,通过Matlab／Simulink仿真分析,证实了所述拓扑结构和控制方法的有效性。     

An ADC histogram test based on small-amplitude waves

This paper deals with a new method improving the static test for analogue-to-digital converters. The method is based on a histogram procedure using as test signals small-amplitude triangular waves superimposed on suitable constant offset values. The histogram is built over the converter fullscale by varying the offset step by step systematically. A small amplitude and a reduced time slope in comparison to the converter range and slew rate, respectively, lead to static test conditions. This procedure allows inexpensive function generators to be used and the test duration to be dramatically reduced. Experimental results of tests aimed at validating, characterizing, and comparing the proposed method on two different converter architectures are presented.     

基于LLC拓扑的宽电压输出车载电源研究

针对电动汽车车载DC-DC变换器的设计问题,对车载DC-DC变换器的宽范围应用需求进行了分析,总结了使用LLC拓扑设计宽范围DC-DC变换器的面临的问题,传统的基波分析法设计理论在宽范围DC-DC变换器中引起的误差很大,通过空载的LLC增益分析对其进行了验证。提出了一种结合基波分析法的限制条件与仿真的新设计方法,使得增益分析的误差大大减小,且对效率优化十分有效。最后搭建了一台2 k W的实验样机对理论分析进行了验证,并根据所提出的设计方法给出了电路关键参数的设计流程。研究结果表明:所设计的样机在10%~100%负载下均能实现软开关,且最高效率达到97.1%。     

模糊控制算法在温控仪中的应用

介绍模糊控制的基本原理,以89C52单片机作为控制核心,采用温度范围宽、精度高的铂热电阻及8位逐次逼近式A/D转换器ADC0808,运用模糊控制算法设计的温控仪可实现如下功能:通过键盘设定所需温度;显示当前温度和设定温度。单片机根据输入的数据,进行智能算法得到控制值,输出脉冲触发信号,通过驱动加热电路和风扇电路进行温度控制。     

基于PID算法控制的智能温控系统的实现

本文介绍了一种基于PID算法控制且带PID参数自整定的智能温控系统。给出了系统各部分的实现方法,详细讲述了本设计巧妙的A/D转化和PID参数自整定的原理及软件实现,最后简要提及了本设计的应用实践及其应用前景。     

渗碳炉温度和碳势在线测控系统

热处理过程控制系统，采用单片机技术解决了传统热电偶温度变送器线性化的非线性残余误差，利用V／F变换器构成的A／D转换器克服了环境干扰所引起的疏失误差，采用数据融合方法，纠正了测量过程中的观测误差，实现了温度和碳势的精确测量。采用智能控制算法，解决了PID控制器调节时间长、超调量大的弊端，实现了被控参数快速跟踪给定值的精确控制。     

多通道可编程A/D转换芯片在现场总线智能从站开发中的应用

介绍一种PROFIBUS-DP智能从站的设计方案，应用美国MAXIM公司的多量程、8通道、12位A／D转换器MAX197实现8路A／D转换，MAX197的并行接口可以与多种微处理器连接，占有较少的CPU资源，因此，能用于较为复杂的系统开发，正是基于此芯片的以上特点，该智能从站采用此芯片作为前端的信号采集和数据处理部分。     

精密直流恒流源开发

开发了一种基于电流闭环反馈控制的数控直流恒流源,介绍了该电路的设计思路.提出由D/A转换器输出为粗调,数字电位器输出为微调的组合D/A输出信号的新方法.将该D/A组合输出信号做为电流环给定值,最小给定值可达0.01 mA.实验结果表明,该电路简单,调整方便,控制精度高,稳定性能好,纹波系数小,具有广泛的应用前景.     

增大A／D带宽的非线性方法及其实现

提出用非线性方法来实现数据采集系统中所要求的具有大带宽的Ａ／Ｄ转换电路。该方法避免了采用价格昂贵的位数高的Ａ／Ｄ,实现的Ａ／Ｄ转换具有良好的动态特性,在实际应用中确实可行,具有较好的通用性。