无源系统

When network system wase stabilized,the equivalent exchange conditions of T-п and voltage source-current source were demonstrated by concept of equivalent exchange and network theorem of stability.

当网络系统达到稳定时，根据网络等效变换的概念，应用网络稳定性原理推导出了T-п形和电压源—电流源的等效变换条件，此方法概念清晰，不仅适用于线性无源网络而且适应线性有源网络，可推广于其它两端、三端或多端线性网络变换。

Through establishing the functional of the source pulse which is based on the concept of "usable energy" in the received pulse and then extremizing the functional by means of the calculus of variations, the mathematical models of the optimized source pulse waveforms are shown to be associated with the eigenfunctions of a homogeneous Fredholm linear integral equation of the second kind. An efficient algorithm is developed for numerically solving the integral equation models.

论文研究了基于延迟反射脉冲序列无源标签的UWB RFID系统的基本工作原理并进行了详细的信号描述和分析，通过建立基于接收脉冲"有效能量"概念的源脉冲波形函数的泛函和使用变分计算泛函极值，得到了相关于第二类齐次Fredholm线性积分方程特征函数的源脉冲波形最优解数学公式模型，并开发了一套有效的数值求解算法。

A passivity controller is introduced to dissipate excess energy and thereby grantee the system's stability.

在从端设计了一个无源控制器用来吸收多余能量，以保证从端无源性，从而保证加入预测器后系统稳定。

This paper describes a design approach of an improved microstrip interdigital filter by Ansoft' Desinger software.

0引言微波带通滤波器是现代电子系统中的关键部件之一。在实际应用电路中，微带滤波器容易与其他无源微波电路和有源微波电路器件集成，实现微波部件和系统的集成化。

In this paper, the basic principle and the power factor of conventional SERDS are discussed. Aiming at its shortage of low power factor, boost chopper type SERDS is adopted. The equivalent circuit of the new scheme is built up, and then vector diagram is used to analyze the power factor of the system, also the harmonic distortion of the system is discussed. The experiment device is established base on a 380F/7.5 kW induction motor and a passive soft switching scheme is applied in order to improve the working condition of IGBT. At last, the experimental results are shown.

本文在分析传统串级调速原理的基础上，对系统的功率因数进行分析；针对传统串级调速系统功率因数低的缺点，采用升压斩波式串级调速系统加以改进；建立了升压斩波式串级调速系统的等效电路并采用向量图法对该系统的功率因数进行详细分析；分析了系统的谐波情况；构建了以7.5kW／380V电机为调速对象的升压斩波式串级调速系统实验装置，给出相应的实验结果；针对斩波器中IGBT处于硬开关状态的缺点，应用无源无损软开关技术予以改善，包括对软开关电路工作原理的分析、参数的设计并给出相应的实验结果。

The feasibility of the two proposed methods is verified by computer simulation.4、A single receiving station passive radar system framework based on Software Defined Radio is proposed. Receiving directly signal, scatted signal use an array antenna simultaneously in the radar system. Therefore, the hardware structure of the system is simplified, Maneuvering and Flexible design are improved.

通过计算机仿真验证提出方法的有效性。4、提出了一种基于软件无线电架构的单接收站无源雷达系统，该系统采用一副天线阵列同时接收直达信号和目标散射信号，简化了系统硬件构成，增加系统机动灵活性能。

For the novel passive detecting radar system,an algorithm based on the existing algorithm of Doppler changing rate is presented to improve the locating accuracy and convergence rate.The Doppler frequency is adopted as the observed quantity,at the same time the EKF algorithm is introduced to process the initial locating results.

针对新型无源探测系统的要求，在原有多普勒频率变化率无源定位算法的基础上，为提高定位精度和收敛速度，提出了增加多普勒频率作为观测量，同时引入EKF算法对原始定位结果进行了处理。

In the past few years, new configurations and modeling techniques for the passives in RF integrated architecture have drawing a great deal of attention.

在过去的十几年中，射频集成系统中的新型无源器件以及各种无源器件的模型建立吸引着研究者们的极大的兴趣与广泛的关注。

As the field of microwave communications professional manufacturer of passive components, Bo Xiang Electronics since its inception is committed to research and development, production and marketing of power splitter, coupler, Combiner, diplexers, filters, power load, such as small and medium-sized 6 Series more than 100 kinds of products, widely used in GSM, CDMA, PHS and other communications networks a variety of distribution systems to low-loss, wideband, high reliability, waterproof dust characterized, its production, processing capability, stable performance , delivered quickly and cost-effective, at present is the biggest kind of passive components, one of professional supplier in 2005, output value of more than 6000 million.

作为微波通信领域的无源器件专业制造商，博翔电子自成立以来致力于研发、生产和销售功分器、耦合器、合路器、双工器、滤波器、中小功率负载等6个系列100多种产品，广泛应用于GSM、CDMA、小灵通等通讯网络的各种分布系统中，以低损耗、宽频带、高可靠性、防水防尘为特点，其生产、加工能力强、性能稳定、交付迅速、性价比高，目前是国内该类无源器件最大的专业供应商之一，2005年产值6000多万元。

RF modules covering GSM, CDMA, TD-SCDMA, WCDMA, WLAN and Wimax wireless communications systems, active modules include power and frequency of the linear power amplifier, transceiver components, modules and integration of selected frequency modules, Passive radio frequency modules, including various types of filters, diplexers, a road, splitters and couplers; wireless network optimization campaign整机including PHS, GSM, CDMA, TD-SCDMA and WCDMA straight-machine, RF Rafah Yuan and indoor distribution systems, digital television, including digital TV mobile wireless transceiver modules, wireless transponders, digital mobile TV repeater, and so on.

射频模块涵盖了GSM、CDMA、TD-SCDMA、WCDMA、WLAN和Wimax等无线通信系统，有源模块包括各种功率和频率的线性功率放大器、收发组件、选频模块和一体化模块等，无源射频模块包括各类滤波器、双工器、合路器、功分器和耦合器等；无线网络优化系列整机包括PHS、GSM、CDMA、TD-SCDMA和WCDMA直放机、射频拉远和室内分布系统等；数字移动电视包括数字电视无线收发模块、无线转发器、数字移动电视直放站等。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。