A 155 Mbps laser diode driver with automatic power and extinction ratio control

An integrated laser diode driver(LDD) driving an edge-emitting laser diode was designed and fabricated by 0.35 μm BiCMOS technology. This paper proposes a scheme which combines the automatic power control loop and temperature com-pensation for modulation current in order to maintain constant extinction ratio and average optical power. To implement tem-perature compensation for modulation current,a novel circuit which generates a PTAT current by using the injecting base current of a bipolar transistor in saturation region,and alternates the amplifier feedback loop(closed or not) to control the state of the current path is presented. Simulation results showed that programmed by choice of external resistors,the IC can provide modu-lation current from 5 mA to 85 mA with temperature compensation adjustments and independent bias current from 4 mA to 100 mA. Optical test results showed that clear eye-diagrams can be obtained at 155 Mbps,with the output optical power being nearly constant,and the variation of extinction ratio being lower than 0.7 dB.     

数学奥林匹克初中训练题(76)

第一试一、选择题 (每小题 7分 ,共 4 2分 )1 .已知a b c=0 ,记M =a22a2 bc b22b2 ac c22c2 ab,N =bc2a2 bc ac2b2 ac ab2c2 ab.则M与N的大小关系是 (　　 ) .(A)M >N　　　 (B)M =N(C)M 相似文献   

K-拟共形亚纯映射的基本不等式及其应用

研究了K-拟共形亚纯映射，建立了平面上K-拟共形亚纯映射的一个基本不等式，应用它们把一些亚纯函数的基本结果推广到拟共形亚纯映射。     

导数是处理函数单调性问题的金钥匙

函数的单调性是高考的热点问题之一。在历年的高考试题中,考查或利用函数的单调性试题屡见不鲜,而且相应的问题都有一定的难度．新教材引进导数,为我们解决函数的单调性及相关问题带来了极大的方便．为了便于掌握,本文把这类问题分类解析,供参考．     

高校招投标过程监督对策研究

随着高等教育规模的不断拓展,高等院校的招投标项目也越来越多．加强和规范对招投标过程监督已经成为各个高校面临和解决的重大课题,文章主要从解决问题的角度,展开对招投标过程监督的对策性研究．以期达到规避问题和规范招投标行为的目的．     

简单实用电感测量电路设计

提出一种采用交流恒流源实现电感测量的方法,采用一些常用元器件实现,电路结构简单,成本低廉.该电路既可用于高校电子电路相关实验室测量电感,也可将其设计成教学实验内容,要求学生自行设计开发,对提高学生的实践动手和创新能力有一定的促进作用.实际测试结果表明,该电路性能稳定,测量精度较高,且具有较强的扩展性.     

浅议文化大发展语境下的畲族文化传承

福建宁德的畲族人口,占全国畲族人口总数的四分之一多,是全国最大的畲族聚居地。在长期的发展过程中,畲族形成了独特的文化,在现代化进程中,因种种原因,传统畲族文化面临礼仪弱化,村落文化缺乏特色,畲族传统技艺处于失传边缘等问题,本文在分析畲族文化传承现状的基础上,提出加强保护,开展抢救性征集工作;以文化为媒,走文化产业化与旅游业共同发展的新路等思路,以期能够不断提高文化创新能力,为传承和保护闽东畲族原生态文化提供新的视角和思路。     

“Happy Seoul for foreigners”: scenes from multicultural life in South Korea

Abstract

Since the mid-2000s, multiculturalism has become a prominent buzzword in South Korea as the nation, which was founded on the myth of a single bloodline, tries to come to terms with its growing foreign population. This article looks at the figure of the industrial migrant worker who, despite being ignored by the mainstream media, has appeared in a handful of independently produced Korean films, including three—Bandhobi (2009 Bandhobi [???]. 2009. Directed by Shin Dong-il. Seoul: IndieStory Inc. [Google Scholar]), Hello, Stranger (2007 Hello Stranger [?? ?? ???]. 2007. Directed by Kim Dong-hyun. Seoul: IndieStory Inc. Host and Guest [???]. 2005. Directed by Shin Dong-il. Seoul: LJ Film. [Google Scholar]), Where Is Ronny? (2008 Where Is Ronny? [??? ???]. 2008. Directed by Sim Sang-kook. Seoul: JinJin Pictures. [Google Scholar])—that will be discussed here in detail. These films, as I will show, not only provide an alternative perspective on immigrant life in Seoul and other parts of the country, which is more often than not represented through the privileged world of the Western “expat,” but also reveal the underlying tensions and contradictions in Korea's approach to multiculturalism as it tries to regulate diversity through the fiat of legislative policy while ignoring the moral and political choices confronting its citizens as they decide whether or not to befriend the other.     

Han-Style Classical Dance Debuts in Beijing

From March 19th to 22nd, Beijing Dance Academy presented its grand-scale dance drama ＂Sorrows of the Tongque Stage＂ in PolyTheater in Beijing. The extraordinarily moving and unforgettable quality of this production lies in what have been called its ＂four extremes＂,     

科研绩效评价的重要工具：中国科学引文数据库

介绍了中国科学引文数据库的基本情况分析了中国科学引文数据库作为科研绩效评价工具所具有的特点。通过中国科学引文数据库的应用提出了几个值得注意的问题