共查询到19条相似文献,搜索用时 453 毫秒
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建立并分析了传输线脉冲变压器的基本电路模型,采用优化次级线电感参数的方法,有效地提高了次级线的阻抗,达到了抑制次级线对输出结果影响的目的。在此基础上,分析并讨论了2种典型的传输线脉冲变压器拓扑结构,在一般情况下,推导了二者输出脉冲电压幅值的计算公式,优化了各次级线电感大小的设计。结果表明,级间无耦合结构从第二级开始电感逐级增加,第n级次级线上电感的最优大小为第二级的(n-1)倍;级间有耦合结构中同一磁芯引起的各次级线电感大小应相同。最后,比较了各类结构的输出,指出级间有耦合结构所需磁芯量最少。 相似文献
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信号传输是随钻测井的重要组成部分, 也是随钻测井进一步发展的瓶颈.针对这个问题, 研究了由NovatekTM提出的基于钻杆内有线传输, 钻杆间电磁耦合传输的随钻信号高速传输方法.首先, 针对钻杆间的电磁耦合结构的对称性, 采用了高效的数值模式匹配法对该耦合结构进行了电磁建模; 然后, 为了优化钻杆间耦合结构的耦合性能, 利用上述的电磁建模方法对该耦合结构进行了仿真分析, 分析了该耦合结构各个参数对耦合性能的影响, 并得出了一些有意义的结论, 该结论能够指导随钻测井信号钻杆间耦合传输的优化设计.另外, 钻杆内传输线利用矩形传输线设计, 设计出了50 Ω 特性阻抗的矩形传输线, 并计算了相关损耗.最后, 通过仿真和实验验证了优化设计的钻杆间耦合传输结构具有非常好的传输性能, 并且仿真和实验结果符合良好.
关键词:
随钻信号传输
数值模式匹配
电磁耦合
矩形传输线 相似文献
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反射系数相位法计算谐振腔外观品质因数的局限性 总被引:1,自引:4,他引:1
分析了反射系数相位法原理中所采用的完全耦合电路和实际等效电路之间的差异,指出采用反射系数相位法计算谐振腔外观品质因数失效的原因是:传输线与谐振腔只通过部分电感耦合;π模双间隙腔中存在耦合槽。定量计算表明:当谐振腔中耦合电感与非耦合电感之比小于0.1,或者缝模频率小于2π模频率时,反射系数相位法就会失效。结合实际谐振腔的参数值进行分析得出:导致反射系数相位法失效的最主要原因是传输线与谐振腔只通过部分电感耦合,并且耦合电感太小。 相似文献
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基于脉冲功率系统磁绝缘传输线的时域仿真结果,分析了磁绝缘建立过程中不同阶段电极间的电子产生的能量损失特性;提出了造成能量损失的因素,包括损失的电子和磁绝缘的电子;给出了影响能量损失大小的因素,包括传输线的线长、半径比和加载脉冲的最大电压、电压的时间变化率等。通过分析不同脉冲功率波形作用下各传输阶段能量损失的起因、大小和影响因素,提出了依据极间的电子分布状态划分传输阶段,及对传输线的总效率分阶段计算的传输效率模型,给出了基于已知的传输效率数值模拟结果对不同阶段的损耗估算并最终估算传输效率的方法。 相似文献
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介绍了预脉冲抑制电感值的选取、大体积电感值的计算、电感在传输线内筒中的绝缘设计和主脉冲在电感上的传输时间以及等效阻抗。根据对电感值与传输线、输出线电压和二极管电流之间关系的数值模拟,预脉冲抑制电感应取值5 μH,并通过实验给出了屏蔽筒中大型电感的计算方法。根据对电感管与传输线内筒之间以及电感匝间电场强度的分析和数值模拟,确定了电感长度630 mm、外径1 160 mm和管径102 mm。通过对电感与传输线内筒之间构成的带绕螺旋传输线等效PSpcie的模拟计算,得到了电感传输线支路上的单次传输时间为349 ns,大于主脉冲的宽度;在主脉冲期间,带绕传输线的阻抗大于25 Ω,也远大于传输线的阻抗。通过内置式预脉冲抑制电感已向水介质同轴线中的气体开关引入了触发高压和工作气体。 相似文献
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求解了两条相同的耦合Frenkel-Kontorova (FK)链在低温、有限温和高温情况下的格波解及色散关系,进而研究了耦合FK双链的晶格振动特点.结果表明,耦合FK双链的色散关系包含一个声学支和一个光学支,两者的频谱范围和频率禁带与FK链的恢复力系数、链间耦合强度系数均有关联,低温和有限温的情况还与外势深度有关系.并且研究发现当链间耦合强度较小时,不存在频率禁带;当链间耦合强度逐渐增加到某一临界值后,频率禁带出现,且随着链间耦合强度增加,频隙不断变大,这是因为光学支随着链间耦合强度增加不断向高频方向移动.此外,还发现带隙结构出现的临界链间耦合强度始终为FK链恢复力系数的2倍,并不受温度的影响.本文还研究了给定链间耦合强度下温度对耦合FK双链色散关系的影响规律.本研究内容可为分析链间界面耦合和温度对晶格的振动特点和物理性质的影响提供理论依据,从而对于能量输运、热调控等实际应用发挥重要的指导作用. 相似文献
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We numerically investigate the excitation of soliton waves in the nonlinear electrical transmission line formed by many cells. When the periodic driving voltage with frequency in the pass band closing to the cutoff frequency is applied to the endpoint of the whole line, the soliton wave can be generated. The numerical results show that the soliton wave generation mainly depends on the self modulation associated with the nonlinear effect. In this study, the lower subharmonic component is also observed in the frequency spectrum. To further understand this phenomenon, we study the dependence of the subharmonic power spectrum and frequency on the forcing amplitude and frequency numerically, and find that the subharmonic frequency increases with the gradual growth of the driving amplitude. 相似文献
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The phenomenon of energy unidirectional transmission is numerically investigated by using a system of two coupled discrete nonlinear electrical transmission lines, each line of the network contains a finite number of cells and has different pass band structures, respectively. Using numerical simulations, we examine the frequency multiplication of the driving frequency and the lattice filtering effect in the line. These lead to the generation of energy unidirectional transmission. In the present work, energy is carried by the second harmonic wave in the pass band. In addition, we also study the dependence of the energy efficiency on the driving amplitude and other parameters of the model, such as the system size and the nonlinear coefficient, by calculation. Furthermore, after detailed numerical simulation, an experimental demonstration is realized. The experimental results agree with those in simulation qualitatively. 相似文献
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A nonlinear chain driven by one end may propagate energy in the forbidden band gap by means of nonlinear modes. For harmonic driving at a given frequency, the process occurs at a threshold amplitude by sudden large energy flow that we call nonlinear supratransmission. The bifurcation of energy transmission is demonstrated numerically and experimentally on the chain of coupled pendula (sine-Gordon and nonlinear Klein-Gordon equations) and sustained by an extremely simple theory. 相似文献
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Eric Tala-Tebue Aurelien Kenfack-Jiotsa Marius Herv Tatchou-Ntemfack Timol on Cr pin Kofan 《理论物理通讯》2013,60(1):93-100
In this work, we investigate the dynamics of modulated waves non-identical coupled nonlinear transmission lines. Traditional methods for avoiding mode mixing in identical coupled nonlinear electrical lines consist of adding the same number of linear inductors in each branch. Adding linear inductors in a single line leads to asymmetric coupled nonlinear electrical transmission lines which propagate the signal and the mode mixing. On one hand, the difference between the two lines induced the fission for only one mode of propagation. This fission is influenced by the amplitude of the signal and the amount of the input energy as well; it also narrows the width of the input pulse soliton, leading to a possible increasing of the bit rate. On the other hand, the dissymmetry of the two lines converts the network into a good amplifier for the ω_ mode which corresponds to the regime admitting low frequencies. 相似文献
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Short-duration electrical pulses play important roles in ultrafast time-domain metrology: they are used to sample rapidly varying signals or as probe signals in ranging radars, time-domain reflectometry and in communication. In this work, we design a nonlinear transmission, which is loaded with resonant tunneling diode to be suitable for microwave A/D conversion. A resonant tunneling diode (RTD) has a negative differential resistance that means when the voltage increases the current decreases. The equivalent circuit of monostable line is given. The simulation is performed by using OrCad program. Results show that a spike is produced and after a charging time constant, another switching occurs. Hence – similar to a relaxation oscillator – the spiking period is determined by the amplitude and frequency of the input current. The transmission line itself ensures the generation and propagation of identical spikes, such as solitons formed after few diodes. 相似文献
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In this paper, soliton propagation in nonlinear transmission lines (NLTLs) periodically loaded with symmetric voltage dependent capacitances is studied. From the lumped element equivalent circuit of the line we have analyzed the influence of nonlinear shunt reactances on soliton propagation characteristics. It is shown that by increasing the non linearity of the C–V characteristic, a faster separation of input signal into solitons is achieved. The fact that frequency multiplication in NLTLs is governed by soliton formation makes the results of this work relevant to understand the influence of nonlinear loading devices on multiplier performance. Since a heterostructure barrier varactor (HBV)-like voltage dependent capacitance has been considered for the nonlinear devices, this study can be of interest for the design of millimeter wave frequency multipliers loaded with HBVs. 相似文献
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We introduce an extended nonlinear Schrödinger (ENLS) equation describing the dynamics of modulated waves in a nonlinear discrete electrical transmission line (NLTL) with nonlinear dispersion. We show that this equation admits envelope dark solitary wave with compact support, with width and speed independent of the amplitude, as a solution. Analytical criteria of existence and stability of this solution are derived. In particular, we show that the modulated compact wave may exist in the NLTL depending on the frequency range of the chosen carrier wave, for physically realistic parameters. The stability of compact dark solitary wave is confirmed by numerical simulations of this ENLS equation and the exact equations of the network. 相似文献
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By using nonequilibrium Green's function method, we study the phonon transport properties in S-shaped graphene nano-junctions (GNJs). Interesting transmission phenomenon is found. The transmission spectrum of low frequency phonon shows forbidden frequency band, by changing the width W2 of the S-shaped GNJs. These low frequency forbidden bands are sensitive to their periodic geometric shape of GNJs. These thermal transport phenomena can be explained by analyzing the phonon transmission coefficient. This paper illustrates the thermal transport mechanisms in the different S-shaped GNJs, and the results could provide significant physical models and theoretical validity in designing the thermal devices based on the GNJs. 相似文献