电感、电容在有线电视传输系统中的应用

介绍电感、电容、串联电路、并联电路的特点,分析电感、电容对高频率的电视载波信号和低频率的交流信号所呈现的特性,对两信号的分离与合成进行阐述,介绍如何利用串联谐振和并联谐振回路对信号进行特殊处理.     

基于准谐振型软开关的高频开关电源变换器

传统高频开关电源变换电路采用硬开关技术,电路功耗大,承受电压、电流应力高。为了克服硬开关技术中开关管在有电流通过的情况下被强制关断,有电压情况下被强制导通而带来的各种不利因素,采用准谐振型软开关技术,即零电流开关（ZCS）准谐振变换器、零电压开关（ZVS）准谐振变换器,由电感、电容组成谐振回路,利用电感、电容之间的能量交换,使主开关管在零电压下导通或零电流下截止,达到了减少开关损耗及电磁干扰的目的。软开关技术在新型开关电源中广泛采用。     

多点同时谐振电路的分析与仿真

电路的谐振现象是对某一频率信号的特殊状态。电路理论中分析多个电感、电容元件串并联时的谐振问题,往往只考虑了在某一频率下电路中发生一点谐振的情况。但如果忽略电感、电容的损耗,同一支路中在某一频率下多点发生了并联谐振,阻抗均为无穷大,它们的电压如何分配？并联支路同时发生串联谐振,阻抗都为零,它们的电流如何分配？本文给出了分压和分流公式,并且通过仿真验证了公式的正确性,同时观察了时域暂态过程。     

多谐振软开关全桥Boost变换器

提出一种利用多谐振实现开关管软开关的全桥Boost变换器.其将变压器漏感作为谐振电感,利用电感与电容谐振实现桥臂开关管和箝位开关管的软开关.桥臂开关管工作于零电流开通与零电压关断状态.有源箝位电路既可抑制变换器工作时可能出现的振荡电压,又可将箝位电容吸收的能量返还回主电路,且箝位开关管工作于零电压开通与零电流关断状态.最后利用硬件实验验证了其多谐振软开关特性.     

电感、电容在有线电视传输系统中的应用

介绍电感、电容、串联电路、并联电路的特点 ,分析电感、电容对高频率的电视载波信号和低频率的交流信号所呈现的特性 ,对两信号的分离与合成进行阐述 ,介绍如何利用串联谐振和并联谐振回路对信号进行特殊处理     

电感、电容在有线电视传输系统中的应用

介绍电感、电容、串联电路、并联电路的特点，分析电感、电容对高频率的电视载波信号和低频率的交流信号所呈现的特性，对两信号的分离与合成进行阐述，介绍如何利用串联谐振和并联谐振回路对信号进行特殊处理。     

一种上变频自供电无线传感器电源管理电路

电线周围的电磁场能量密度低,电磁换能器采集到的能量通常无法直接驱动无线传感器正常工作.论文采用上变频技术,设计了一种自供电电源管理电路来提高能量采集效率.由于电路的输出功率与品质因数成正比,且品质因数的大小与电路谐振电容的根号值成反比,因此通过提高电路的工作频率来减小谐振电容值,可以使高品质因数的电路产生更高的输出功率,进而增加能量采集效率.实验结果表明,该电路的最大能量采集效率是传统桥式整流电路的2.1倍.当电线中通过1A、50Hz的交流电时,电源管理电路最大采集功率为780μW,能量采集效率达到48.75%.当管理电路中超级电容能量积累达到一定程度,电容放电驱动无线传感器工作.     

一种采用LC谐振电路的高频差分有源电感

提出了一种采用LC并联谐振电路的新型差分有源电感,实现了宽的工作频带、高的Q值、较大的电感值和可调谐功能.采用无源电感和MOS晶体管可变电容构成LC谐振电路,减小了等效串联电阻和等效并联电容,在增大电感值、Q值的同时,扩大了工作频带.仿真结果表明,在2～7.6 GHz频率范围内,该新型差分有源电感的电感值大于26 nH...     

基于RLC串联谐振实现电感的测量

介绍了一种测量电感的新方法,以RLC串联谐振电路为基础,将待测电感与电阻、电容串联起来组成RLC振荡电路;当电路达到谐振状态时,当电容已知,可得待测电感的值。此方法测量原理简单,操作方便,测量结果精确度较高,值得推广。     

一种采用开关阶跃电容的压控振荡器(上):调谐特性的理论分析

针对采用阶跃可变电容的电感电容压控振荡器电路,本文提出了一种振荡器调谐特性的时域分析方法--周期计算技术. 通过对电感电容谐振回路中电感的I-V曲线分析,详细地阐述了阶跃可变电容能够实现线性压控的物理机理和本质. 对差分调谐电感电容压控振荡器的调谐特性也进行了详细的分析. SPICE电路仿真验证了调谐特性理论分析的正确性.     

具有电或磁耦合关系谐振电路的谐振频率

采用本征值理论分析与电路仿真两种独立的方法,定量计算了具有电耦合或磁耦合关系谐振电路的谐振频率随耦合电容或耦合系数大小的变化关系,两种耦合电路的谐振频率表现出不同的变化规律。这种耦合谐振电路的分析为实际电路设计过程中利用耦合类型及耦合强度对谐振频率进行调谐开辟了新的途径,扩展了现有教学中无耦合谐振电路的教学内容。     

一种贴片电感电容测量新方法的研究

为了得到贴片电感电容在微带电路中的精确值,提出一种基于矢量网络分析仪的电感电容自动测量系统.依据LC谐振电路和微带传输线理论设计制作测量夹具,通过Matlab编写田口优化算法计算得到已知电感电容值,并基于GPIB接口对矢量网络分析仪实现程控,采用VC ＋＋6.0工具开发自动测量系统的用户界面.给出了具体的设计思路和测量方法,实测结果表明,该系统实现了对微带电路中电感电容的快速精准测量,具有很高的实用价值.     

无隔模带磁控管谐振系统的理论分析与仿真

为了提高磁控管稳定性,需要研究各耦合因素对磁控管谐振频率及模式分隔度的影响。该文采用等效电路的方法,给出了无隔模带磁控管在电容、电感耦合下的谐振频率及模式分隔度的表达式,并分析谐振频率随模数的变化趋势及电感、电容耦合强弱对模式分隔度的影响。采用CST-MWS软件对不同阴极半径及顶盖高度的谐振系统的谐振频率进行仿真,并将仿真结果与理论结果进行对比。理论分析与计算机仿真表明,对于无隔模带磁控管谐振系统,电容耦合使谐振频率随模数的增大而增大,电感耦合使谐振频率随模数的增大而减小;两者分别通过增大和降低模频率从而增大模式分隔度,两者共同作用时模谱图取决于占主导地位的耦合因素。     

General Treatment of Klystron Resonant Cavities

Klystron resonant cavities are treated for general cases and their equivalent circuits are theoretically determined, which allows a fairly accurate estimate of resonant properties. It is shown that a reentrant cavity is expressed as a low-frequency series LCR/sub se/ circuit or a shunt LCR/sub sh/ circuit, taking L as the inductance of a toroidal coil with one turn and with a cross section the same as the cavity, C as the gap capacitance plus the equivalent capacitance of the cavity, and R/sub se/ or R/sub sh/ as the equivalent series or shunt resistance of the cavity at resonance. The introduction of the equivalent cavity capacitance has proved to be very effective. The formulas derived here enable one to calculate the resonant frequency within an error of a few per cent and the shunt resistance and the Q within an error of several tenths of a per cent in most cases, and thus should prove to be very useful to the designer of microwave circuits.     

Varactor-tuned integrated Gunn oscillators

Electronic tuning of Gunn diodes in hybrid integrated circuits has been studied. Microstrip transmission lines were used to form resonant circuits into which a Gunn diode and a varactor diode were mounted to provide the microwave power and frequency tuning, respectively. Basically, two types of circuits have been investigated. The first is a half-wavelength open-circuited microstrip `cavity' with this transmission line and the varactor diode attached between the end of the cavity and an RF ground. The second is a lumped LC circuit in which the inductance of a short high-impedance microstrip line is resonated with the lumped capacitance of the varactor diode. The latter circuit provides a tuning range of over 10 percent at 7.5 GHz. The power output varies within 2 dB in the tuning range.     

Analysis and optimization of a nondissipative LC turn-offsnubber

A nondissipative LC turn-off snubber is used to reduce the voltage stress on a switching transistor, which is caused by the energy stored in the transformer leakage inductance. A detailed analysis of the fundamental characteristics of a buck-boost converter with an LC snubber is given, clarifying the effect of the snubber capacitance. In particular, it is found that the transformer current increases with the snubber capacitance, the transistor surge voltage and power loss are evaluated, and the optimum value of the snubber capacitance is derived. The most effective value of the snubber inductance is also discussed     

On the High-Speed Turn-Off of a Power Transistor by a Small Saturable Core

An effective method for reducing the size and weight of the switching dc-dc converter is to increase the switching frequency. To accomplish this with no deterioration in efficiency, it is necessary to suppress the switching loss per cycle by shortening the switching time. An efficient dc-dc converter operating at the megahertz region is presented. The turn-off time is shortened by using the current feedback and the core saturation. The turn-off mechanism is analyzed with the equivalent circuits. As a result, it is found that the excess carrier in the base region is discharged quickly by the large reverse base current, which flows when the energy stored in the base-emitter capacitance of the power transistor is transferred to the saturated inductance of the core with high frequency oscillation.     

数-相量子化及介观电路在自由热态下的量子效应

利用数-相量子化方案,将介观LC电路等效为一个谐振子.通过相干态表象和算符正规乘积形式,简捷地给出了自由热态的Wigner函数,同时借助于量子算符及其Weyl-Wigner对应研究了体系中电荷数及相位差在自由热态下的量子效应.结果表明,体系中电荷数及相位差在自由热态下的量子涨落不仅和电路中器件的参数有关,而且还和温度有关,且储存于电感中的平均能量和电容中的平均能量分别相等.这一研究结果支持了介观电路数-相量子化新方案,对介观电路的量子化和电路的量子效应的研究具有很好的理论指导意义.     

On the Superposition of Inductive and Capacitive Coupling in Crosstalk-Prediction Models

An examination of traditional low-frequency crosstalk-prediction models is presented. From the exact solution of the transmission-line equations for a 3-conductor line, it is shown that superimposing crosstalk contributions due to mutual inductance and mutual capacitance between the two circuits is valid for a sufficiently small frequency. The widely held notion that one may superimpose the effects of both mutual and self elements ( inductance and capacitance) is shown to be incorrect.     

Resonant clocking using distributed parasitic capacitance

A resonant-clock generation and distribution scheme that uses the inherent, parasitic capacitance of the clocked logic as a lumped capacitor in a negative-resistance oscillator is described. Clock energy is resonated between inductors and the parasitic, local clock network to save power over traditional clocking methodologies. Theory predicts that the data passing though the clocked logic will change the clock frequency by less than 1.25%. A resonant clock test chip was designed and fabricated in an IBM 0.13-/spl mu/m partially depleted SOI process. Although the test chip was designed to operate in the gigahertz range using integrated inductors, startup difficulties required the addition of external inductance to reduce the resonant frequency so that the effects of the parasitic capacitance could be measured. The parasitic capacitance is approximately 40 pF per clock phase, resulting in a clock frequency between 106 and 146 MHz, depending on biasing. At its most efficient bias point, the clock dissipated 2.09 mW, which is approximately 35% less power than a conventional, buffer-driven clock. The maximum period jitter measured in the resonant clock due to changing data in the clocked latches was 55 ps at 124 MHz, or 0.68% of the clock period.