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刘振华 《中国电子科学研究院学报》2005,(6):38-40,44
本文分析了开关电源传导干扰的产生机理,讨论了开关电源传导发射的实验室测量方法。对实际的开关电源进行了测试和分析,建立了传导干扰分析模型,最终得出了开关电源传导干扰的特点,进而提出了建立工程仿真模型的方法。 相似文献
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开关电源干扰的抑制方法是开关电源研制成功的关键。抑制开关电源的干扰,首先要从干扰源入手,主要通过精心地设计电路,优选电路元器件,调整电路参数,合理安排元器件位置和接地;其次采用滤波和屏蔽等惯用方法。其中,很大一部分是工艺问题。本文从这些角度来探讨,如何有效地抑制脉宽调制(PWM)型开关电源的射频干扰和传导干扰。 相似文献
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电视机用开关电源普遍存在干扰大的缺陷,本文通过对开关电源在电视机中造成干扰的分析,提出了一种新型无干扰开关稳压电源。该电路具有以下特点:电路中不外加任何抗干扰元件,可降低成本;用电路参数(一只电阻器)来控制开关干扰的强弱,生产性好;占空系数能够从0~1之间变化,稳压范围比其它开关电源宽;此外,电路本身还具有一定的保护功能。 相似文献
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为提高PFM开关电源控制电路的抗电磁干扰能力,分析了PFM模式开关电源控制电路的抗电磁干扰原理,提出了随机载波频率调制技术和相应的电路实现方法;列举了几种电源系统抗电磁干扰设计技术,包括ESD保护结构的抗EMI设计方法、电源上干扰的去除方法和基于电压检测电路的抗干扰设计方法。将以上抗干扰设计技术应用在PFM模式开关电源控制电路SX1618中,采用1μm 40V高压工艺设计,通过进行流片和封装,并将之应用在实际的开关电源中,其传导EMI通过了相应标准的测试。 相似文献
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传导性电磁干扰是开关电源的主要干扰源,国际电磁兼容测试标准规定的电源产品EMC 指标己成为开关电源的一个重要性能参数。文中从开关电源的工作原理和元器件特性出发,对开关电源的电磁干扰机理进行分析,研究抑制开关电源中传导干扰的措施。着重研究了滤波器的抑制措施,从实际应用角度对滤波器中的电感、电容等元件的特性进行了分析,给出了实用的滤波电路和元件参数。真空接触器中开关电源的电磁传导干扰抑制的应用结果表明,使用滤波器等抑制措施对电磁传导干扰有很好的抑制效果。 相似文献
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电磁干扰对开关电源的效率和安全性影响成为人们关注的热点。文中分析了开关电源中电磁干扰产生的原因,提出了抑制干扰的有效措施。 相似文献
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针对光传输系统的特点与要求, 基于有限域提出了一种新颖的扩展非规则重复累积准循环低密度奇偶校验码(eIRA-QC-LDPC)构造方法, 该构造方法可根据实际需要灵活地调整码长码率, 利用此方法构造了一种码率为0.937的novel-eIRA-QC-LDPC(4599,4307)码。仿真结果表明: 在误码率(BER)为10-7且码率均为0.937的情况下, 该novel-eIRA-QC-LDPC(4599,4307)码比ITU-T G.975中RS(255,239)码和ITU-T G.975.1中LDPC(32640,30592)码的净编码增益(NCG)分别改善了约2.13和1.33dB, 比用SCG构造方法构造的SCG-eIRA-LDPC(3717,3481)码和基于阵列码构造方法构造的Array-eIRA-QC-LDPC(4560,4275)码的净编码增益分别提高了约0.24和0.41dB, 距离香农限约1.07dB。因而该构造方法所构造的eIRA-QC-LDPC码具有更好的纠错性能, 更适合高速长距离的光传输系统。 相似文献
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利用一套自己研制的实验装置对VCSEL的偏振相关特性进行了研究,包括偏振相关静态LI曲线、光谱以及时间响应等,分析了偏振模式分配噪声的产生机理。在此基础上提出了实现完全偏振稳定的设计思路。 相似文献
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Erik Bruun 《Analog Integrated Circuits and Signal Processing》1997,12(1):71-78
The definition of the current conveyor is reviewed and a multiple-output second generation current conveyor (CCII) is shown to combine the different generations of current conveyors presently existing. Next, noise sources are introduced, and a general noise model for the current conveyor is described. This model is used for the analysis of selected examples of current conveyor based operational amplifier configurations and the noise performance of these configurations is compared. Finally, the noise model is developed for a CMOS current conveyor implementation, and approaches to an optimization of the noise performance are discussed. It is concluded that a class AB implementation can yield a lower noise output for the same dynamic range than a class A implementation. For both the class A implementation and the class AB implementation it is essential to design low noise current mirrors and current sources, and with the class AB design, the current mirror and current source noise can be reduced by using small values of bias current without compromising the maximum available output current. 相似文献
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Digital harmonics, which may reduce the radio frequency sensitivity of a system, can be coupled with an antenna in a mobile handset. This letter presents a decoupling method for increasing the isolation between digital harmonics on a flexible printed circuit board (FPCB) and an antenna in terms of the ground mode current and the concept of reaction. We model the signal and ground lines in an FPCB as a loop circuit exciting a ground mode current and demonstrate a simple but efficient decoupling method for reducing the excited ground mode current. 相似文献
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Arie F. Arbel 《Analog Integrated Circuits and Signal Processing》1995,7(3):221-242
A comparison is made between the noise performance of current mode- and voltage mode feedback amplifiers, in terms of their noise figureF
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andF
v
, respectively. WhereasF
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of a well designed voltage amplifier is dominantly affected by the input stage only, all stages of a current amplifier including the feedback network may potentially contribute toF
i
. This paper investigates the transferfunction to the output of the various noise sources of current mode feedback amplifiers, whose full recognition is essential in order to design CMFA's of reasonable noise performance. Also discussed is the effect the dynamic range of a postamplifier may have on its noise figure. Although the bulk of this paper deals with postamplifiers, the important subject of low noise current amplification is covered as well.A short version of this paper has been published in Proceedings ECCTD'93, pp. 1565-1568.1. Patent 5410271, USA 相似文献
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低噪声高共模抑制比的运算放大器是将套筒式共源共栅结构、差分输出和共模负反馈相结合,设计出的一种新型运算放大器.基于SMIC0.18 μm工艺模型对电路进行设计,仿真结果表明该电路的开环增益为82.3 dB,相位裕度为66°,共模抑制比为122 dB,增益平坦带宽为15 MHz,噪声为7.781 nV/sqrt (Hz),达到设计要求. 相似文献