在无线通信系统全面进入3G并开始迈向 4G的过程中,使用数字预失真技术(Digital Pre-distortion,以下简称DPD)对发射机的功放进行线性化是一门关键技术。功率放大器是通信系统中影响系统性能和覆盖范围的关键部件,非线性是功放的固有特性。非线性会引起频谱增长(spectral re-growth),从而造成邻道干扰,使带外杂散达不到协议标准规定的要求。非线性也会造成带内失真,带来系统误码率增大的问题。
上传时间: 2013-10-19
上传用户:yy_cn
The LTC®1966 is a true RMS-to-DC converter that uses aDS computational technique to make it dramatically simplerto use, significantly more accurate, lower in powerconsumption and more flexible than conventional logantilogRMS-to-DC converters. The LTC1966 RMS-to-DCconverter has an input signal range from 5mVRMS to1.5VRMS (a 50dB dynamic range with a single 5V supplyrail) and a 3dB bandwidth of 800kHz with signal crestfactors up to four.
上传时间: 2013-10-12
上传用户:qilin
Precision 16-bit analog outputs with softwareconfigurableoutput ranges are often needed in industrialprocess control equipment, analytical and scientificinstruments and automatic test equipment. In the past,designing a universal output module was a daunting taskand the cost and PCB real estate associated with thisfunction were problematic, if not prohibitive.
上传时间: 2014-12-23
上传用户:如果你也听说
High input impedance and a wide input range are twohighly desirable features in a precision analog-to-digitalconverter, and the LTC®2449 delta-sigma ADC has both.With just a few external components, the LTC2449 formsan exceptional measurement system with very high inputimpedance and an input range that extends 300mV beyondthe supply rails.
上传时间: 2013-11-02
上传用户:ywcftc277
Designers of signal receiver systems often need to performcascaded chain analysis of system performancefrom the antenna all the way to the ADC. Noise is a criticalparameter in the chain analysis because it limits theoverall sensitivity of the receiver. An application’s noiserequirement has a signifi cant infl uence on the systemtopology, since the choice of topology strives to optimizethe overall signal-to-noise ratio, dynamic range andseveral other parameters. One problem in noise calculationsis translating between the various units used by thecomponents in the chain: namely the RF, IF/baseband,and digital (ADC) sections of the circuit.
上传时间: 2014-12-05
上传用户:cylnpy
Control systems are becoming increasingly dependent on digital processing and so require sensors able to provide direct digital inputs. Sensors based on time measurement, having outputs based on a frequency or phase, have an advantage over conventional analogue sensors in that their outputs can be measured directly in digital systems by pulse counting.
上传时间: 2013-10-08
上传用户:wuyuying
This application note describes a Linear Technology "Half-Flash" A/D converter, the LTC1099, being connected to a 256 element line scan photodiode array. This technology adapts itself to handheld (i.e., low power) bar code readers, as well as high resolution automated machine inspection applications..
上传时间: 2013-11-21
上传用户:lchjng
前面讨论了很多内容,基本上涉及了有关PCB板的绝大部分相关的知识。第二章探讨了传输线的基本原理,第三章探讨了串扰,在第四章里我们阐述了许多在现代设计中必须关注的非理想互连的问题。对于信号从驱动端引脚到接收端引脚的电气路径的相关问题,我们已经做了一些探究,然而对于硅芯片,即处于封装内部的IC来说,其信号传输通常要通过过孔和连接器来进行,对这样的情况我们该如何处理?在本章中,我们将通过对封装、过孔和连接器的研究,阐述其原理,从而指导大家在设计的时候对整个电气路径进行完整地分析,即从驱动端内部IC芯片的焊盘到接受器IC芯片的焊盘。
标签: High-Speed Digital System desi
上传时间: 2013-11-24
上传用户:maizezhen
高速数字系统设计下载pdf:High-Speed Digital SystemDesign—A Handbook ofInterconnect Theory and DesignPracticesStephen H. HallGarrett W. HallJames A. McCallA Wiley-Interscience Publication JOHN WILEY & SONS, INC.New York • Chichester • Weinheim • Brisbane • Singapore • TorontoCopyright © 2000 by John Wiley & Sons, Inc.speeddigital systems at the platform level. The book walks the reader through everyrequired concept, from basic transmission line theory to digital timing analysis, high-speedmeasurement techniques, as well as many other topics. In doing so, a unique balancebetween theory and practical applications is achieved that will allow the reader not only tounderstand the nature of the problem, but also provide practical guidance to the solution.The level of theoretical understanding is such that the reader will be equipped to see beyondthe immediate practical application and solve problems not contained within these pages.Much of the information in this book has not been needed in past digital designs but isabsolutely necessary today. Most of the information covered here is not covered in standardcollege curricula, at least not in its focus on digital design, which is arguably one of the mostsignificant industries in electrical engineering.The focus of this book is on the design of robust high-volume, high-speed digital productssuch as computer systems, with particular attention paid to computer busses. However, thetheory presented is applicable to any high-speed digital system. All of the techniquescovered in this book have been applied in industry to actual digital products that have beensuccessfully produced and sold in high volume.Practicing engineers and graduate and undergraduate students who have completed basicelectromagnetic or microwave design classes are equipped to fully comprehend the theorypresented in this book. At a practical level, however, basic circuit theory is all thebackground required to apply the formulas in this book.
上传时间: 2013-10-26
上传用户:缥缈
OPTOELECTRONICS CIRCUIT COLLECTION AVALANCHE PHOTODIODE BIAS SUPPLY 1Provides an output voltage of 0V to +80V for reverse biasingan avalanche photodiode to control its gain. This circuit canalso be reconfigured to supply a 0V to –80V output.LINEAR TEC DRIVER–1This is a bridge-tied load (BTL) linear amplifier for drivinga thermoelectric cooler (TEC). It operates on a single +5Vsupply and can drive ±2A into a common TEC.LINEAR TEC DRIVER–2This is very similar to DRIVER–1 but its power output stagewas modified to operate from a single +3.3V supply in orderto increase its efficiency. Driving this amplifier from astandard +2.5V referenced signal causes the output transistorsto have unequal power dissipation.LINEAR TEC DRIVER–3This BTL TEC driver power output stage achieves very highefficiency by swinging very close to its supply rails, ±2.5V.This driver can also drive ±2A into a common TEC. Operationis shown with the power output stage operating on±1.5V supplies. Under these conditions, this linear amplifiercan achieve very high efficiency. Application ReportThe following collection of analog circuits may be useful in electro-optics applications such as optical networkingsystems. This page summarizes their salient characteristics.
上传时间: 2013-10-27
上传用户:落花无痕