PWM整流器高功率因数的实现

论述了交流斩波电路中控制部分的工作原理，并对该电路中电抗器的取值进行了计算。采用16位80C196KC单片机能使控制电路非常简单，并容易实现高频开关器件整流器的高功率因数。     

Call Admission Policies Based on Calculated Power Control Setpoints in SIR-Based Power-Controlled DS-CDMA Cellular Networks

In this paper, we develop call admission control algorithms for SIR-based power-controlled DS-CDMA cellular networks. We consider networks that handle both voice and data services. When a new call (or a handoff call) arrives at a base station requesting for admission, our algorithms will calculate the desired power control setpoints for the new call and all existing calls. We will provide necessary and sufficient conditions under which the power control algorithm will have a feasible solution. These conditions are obtained through deriving the inverse of the matrix used in the calculation of power control setpoints. If there is no feasible solution to power control or if the desired power levels to be received at the base station for some calls are larger than the maximum allowable power limits, the admission request will be rejected. Otherwise, the admission request will be granted. When higher priority is desired for handoff calls, we will allow different thresholds (i.e., different maximum allowable power limits) for new calls and handoff calls. We will develop an adaptive algorithm that adjusts these thresholds in real-time as environment changes. The performance of our algorithms will be shown through computer simulation and compared with existing algorithms.     

Effect of Additives on Magnetic Properties of High Frequency MnZn Power Ferrite

In keeping with the advance of more compact and more power-saving electronic equipment, the demand is increasing for smaller and more efficient switching power supply. Therefore, it is necessary to provide the adequate magnetic power ferrite materials to satisfy the demand. Such ferrite materials have to meet the following main requirement: 1) high initial permeability (μ i ); 2) high saturation magnetic induction (Bs); 3) high Curie temperature (Tc); 4) high electrical resistivity (ρ ); 5)…     

微波功率放大器预失真线性化技术分析

给出了两种基本形式的预失真线性化电路,对其工作原理和技术特点进行了分析。     

工频电场对ADSS光缆特性的影响

随着电压等级的不断提高,超高压输电线路发展非常迅速.但是这些架空输电线路在运行时,附近存在较高的电场,对周围物体和公用走廊的其它线路会产生影响.电压等级越高,产生的电场影响越大.输电线路产生的电场越来越受到人们的重视.尤其是对于超高压输电线路,由于在电力铁塔上同塔悬挂全介质自承式光缆(ADSS),因此分析工频电场对ADSS光缆特性的影响非常必要.     

一种VDSL上行链路自适应功率回馈方案

上行链路功率回馈技术(UPBO：upstream power back-off)是VDSL(very high-speed digital subscriber lines)系统中的关键技术，它用于抵消同一电缆中短线对长线引起的严重的远端串扰(FEXT:far-end crosstalk)。文中从功率控制的角度分析了基于迭代注水的自适应UPBO方案，并进行了性能仿真分析。     

电源设备的功率因数校正技术

功率因数校正(PFC)技术能提高电源设备的电源利用率，减少谐波。文中介绍了功率因数的定义，功率因数校正技术及其应用实例。     

供电器可供放大器最大级数的计算

有线电视电缆网采用供电器进行集中供电，要计算一个额定容量的供电器可供放大器的最大级数，算式是很复杂的，而用VisaulFOXPRO6．0编写一个小程序，利用电脑对上述问题进行处理，就变得简单易用。     

TOPSwitch集成电路在DC/DC电源设计中的应用

文章介绍了PWM／MOSFET二合一的TOPSwitch系列集成电路及其在DC／DC电源设计中的应用，还介绍了基本反馈方式的DC／DC拓扑结构及其改进措施，并对由TOPSwitch集成电路构成的DC／DC电源进行了抗中子实验。     

一类广义积分integral from n=0 to ∞(((sin(θ_x))/x)~ndx)的计算

利用三角函数幂公式、L′Hospital法则、分部积分公式,得到含有三角函数的第一类广义积分integral from n=0 to ∞(((sin(θ_x))/x)~ndx)的计算公式,其中n≥1且θ≠0.