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31.
率放大器作为发射机中最核心的模块之一,如何同时提高其效率和线性度一直是人们研究的热点。文章主要分析了AB类功率放大器中的主要非线性源—栅源电容对电路性能的影响,并且使用了一个PMOS管并联的技术来补偿这种影响,最后利用这种技术,采用JAZZ0.25um RF CMOS工艺实现了一个可应用于2.45GHz WLAN的高效率高线性度的AB类功率放大器,三阶交调(IM3)项为-12dBm,输出功率为26dBm,功率附加效率(PAE)为44%。 相似文献
32.
A reliability evaluation approach based on the development process of the structural nonlinearity is presented. The traditional structural system reliability theory for structural safety regarding combination of failure modes is first revisited. It is seen that it stemmed from, and was heavily affected by, the assumption of perfect elasto-plasticity of materials. This will make the number of the failure modes increase in a non-polynomial form against the number of the potential plastic hinges. Moreover, the above methodology does not work appropriately in the case of nonlinearity in general form other than perfect elasto-plasticity, as commonly encountered in engineering practice. Discussions show that total information of the structure is involved in the development process of its nonlinearity, be it a deterministic case or stochastic counterpart. The information needed for reliability evaluation of structures could be extracted, for example, by capturing the probabilistic information of the extreme value of the corresponding response, which could be obtained by using the probability density evolution method. Therefore, the reliability evaluation for structural safety could then be directly evaluated without searching the failure modes. Taking a 10-bar truss as an example, the proposed method is theoretically elaborated and numerically exemplified. 相似文献
33.
微波辐射计的功率非线性对标定天线温度的影响 总被引:1,自引:0,他引:1
微波辐射计通过两点定标反演天线温度依赖的是辐射计的输入功率与输出电压的线性关系。通过分析平方律检波器的输入功率与输出电压的关系,导出非线性系数与由口面定标法反演的天线温度误差的关系式。定量说明了功率非线性度引入误差的大小.通过计算分析得出两种定标系统(地面遥感和星载遥感)对功率非线性度的要求。 相似文献
34.
In anormalous dispersion of monomode optical fiber,optical solitons are evolvedfrom optical pulses when the dispersion is balanced by the nonlinearity.Undistorted transmissioncan be realized by using optical solitons,which can offer much greater the transmission capacityand extend the repeater spacing of the fiber communication system.The mechanism of thegeneration of optical solitons is expounded.A few forms of nonlinear transmission equationare obtained by using a concise method.The general complete expression of elementary solitonsolution of the nonlinear transmission equation without loss is given,and the design of the solitontransmission system is discussed. 相似文献
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Complexity, class dynamics, and distance learning 总被引:2,自引:0,他引:2
Kate Kiefer Author Vitae 《Computers and Composition》2006,23(1):125-138
Classroom participants learn early on that each classroom has its own dynamic comprised of personalities, motivation levels, skills, and other variables. This paper explores features of complexity theory—nonlinearity and emergent self-organization—relevant to dynamics in physical or virtual classrooms. These central notions of complexity theory and their importance in composition classrooms help explain why students in virtual classrooms are often less successful than their physical classroom counterparts in negotiating the eddies of virtual interactions. The paper closes with a brief consideration of how teachers can interrogate all the elements of teaching and classroom context (whether physical or virtual) to influence the emergent dynamic of our classrooms. 相似文献
38.
This paper provides experimental validation of the digital first-order periodic error reduction scheme described by Chu and Ray. A bench-top setup of a single-pass, heterodyne Michelson interferometer, designed to minimize common error contributors such as Abbe, dead path and environment, is described. Linear, reciprocating motion generation is achieved using a parallelogram, leaf-type flexure. Periodic error amplitude is varied through independent rotation of a half wave plate and polarizer. Experimental results demonstrate that the correction algorithm can successfully attenuate first-order error to sub-nm levels for a wide range of frequency mixing conditions. 相似文献
39.
The aim of this work was to analyze the main equilibrium equations used for grains to find the best way to represent the equilibrium conditions between mustard seed and air. The experimental study was based on the static method using saturated salt solutions to regulate the vapor pressure of the air surrounding the seeds. Since the majority of the sorption equilibrium equations are nonlinear, procedures available in the literature were used to validate the statistical properties of the least squares estimators. To discriminate, between five equations that represent the sorption equilibrium isotherms of mustard seeds, an approach based on nonlinear measures was used in this work. Results show that the Halsey modified equation is the best one to describe the experimental data. 相似文献
40.
This paper discusses the degree of completeness of cryptographic functions, which is one of the cryptographic criteria should be considered in the design of stream ciphers. We establish the re- lationships between the degree of completeness and other cryptographic criteria. For resilient Boolean functions, a method to enhance the degree of completeness is proposed, while the nonlinearity and the algebraic degree do not decrease. Moreover, two constructions of resilient functions are provided, which have optimal degree of completeness, high nonlinearity, and high algebraic degree. 相似文献