多频调制信号通过失谐电路的数学表示与波形

给出了多频调制信号通过单谐振失谐电路的数学表达式，用科学与工程计算软件(MATLAB)实现了对信号的分析与描绘．通过改变程序中的电路参数或者信号参数，可以模拟多种情况下的信号时域波形，从而对信号通过谐振电路进行理论分析或对电路进行改进．     

微波功率放大器的小信号S参数设计方法

微波功率放大器设计需要大信号S参数,但大多数情况下,设计者只有小信号S参数和静态I-V曲线。文章提供了一种在此条件下进行设计的方法:即首先利用ADS软件,将功率管的小信号S参数制成S2P文件供仿真电路使用;再通过静态I-V曲线计算出输出负载阻抗,利用软件的优化功能将输出电路共扼匹配到本阻抗;对于输入电路,则按照最大增益的原则使源阻抗与输入阻抗共扼匹配;最终对整个电路进行优化,完成整个电路的设计。     

一种多功能有源滤波器电路仿真设计与分析

根据电路直接型传递函数,对一种多功能有源滤波电路的频率特性进行了分析,给出了该种电路的低通、带通和高通参数仿真设计方法。该电路用于无线数字传输中,作为发射端的前置滤波电路而获得较为理想的FSK信号;同时在频分多址通信系统中,利用该电路可实现多种信号频段的划分。本次设计采用先进的仿真软件Multisim对有源滤波电路进行仿真,仿真研究与理论分析一致,为获得该类有源滤波器的电路设计参数提供了EDA手段和实验依据．     

变形蔡氏电路的混沌保密通信仿真研究

为了便于蔡氏混沌电路的集成,设计了具有模拟电感的蔡氏混沌电路。在此电路基础上,进一步设计了混沌保密通信电路,并进行了仿真研究。结果表明,合适参数的发送信号在该混沌保密通信电路中能被很好地掩盖,也很难被窃听,发送信号和保密通信电路解调出来的信号是一致的,说明该通信电路具有很好的保密性能。但是当发送信号的幅度和频率超过一定值时,该混沌保密通信电路几乎不能实现对发送信号的保密。     

脉冲信号作用下介观互感耦合电路的量子效应

研究外加脉冲信号对介观互感耦合电路量子态的影响,结果表明:当电路参量不变时,通过控制脉冲信号的参量的变化可以调节介观互感耦合电路量子态的变化.而当脉冲信号宽度满足一定的条件时,系统的量子态可以保持不变,该条件与电路的参数有关.     

一个混沌电路的特性及其在保密通信中的应用研究

设计了一个实际混沌电路,并用EWB软件对该电路产生的混沌信号特性进行了仿真研究.同时对电路进行了实验研究,并在示波器上观察到了丰富的混沌信号.实验与仿真结果表明:该电路产生的混沌信号稳定,电路处于混沌状态时的参数可调节范围大.另外还用该电路成功地进行了混沌掩盖保密通信的仿真研究与实验研究.     

一种基于DSP和FPGA的雷达信号分选电路设计

设计了一种基于DSP和FPGA的雷达信号分选电路,对密集的雷达信号进行分选识别。系统利用FPGA采集信号的特征参数以及对参数进行预处理;采用了累积差值直方图算法,根据信号脉冲宽度对数据分组,多片DSP协同处理实现信号分选。工程实践表明:该电路对常规雷达信号分选效果良好,处理速度快,系统可靠性好。     

倍压整流电路参数分析与设计

对倍压整流电路的原理进行了简要的介绍,通过Protel DXP自带的混合信号仿真器验证了电路中各个参数对输出电压大小以及纹波的影响,同时还分析了电路中不同电容取值的改变对输出的影响,为倍压整流电路的参数选择提供理论依据,并实际搭建电路,测试波形,验证仿真结果。     

运用变量代换求阻抗极值点

在正弦交流电路中，电路阻抗是电路参数和信号频率的函数，当电路某一参数或信号频率发生变化时，二端网络的总阻抗会出现极值，因此常会遇到阻抗极值点的计算。由于复阻抗一般由Ｒ、ｘＬ、ｘＣ构成复数分式，其模及其对某参数的导数式非常繁杂，以致某些看似简单的习题，...     

混沌信号发生器的研究

以改进的蔡氏电路为核心电路,用实际元器件制作了一个混沌信号发生器.并用EWB电子设计自动化软件对该混沌信号发生器产生的混沌信号的特性进行了仿真研究和实验研究,在示波器上观察到了丰富的混沌信号波形.表明该混沌信号发生器能够产生稳定的混沌信号波形,且电路处于混沌状态时的参数可调节范围更大,因而也更易应用于实际.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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