RLC-ladder-network synthesis: signal-flow-graph approach

Using signal-flow graphs, a theorem is proved which gives the immittance functions of the ladder network of which the voltage transfer function is to be realised, and then the realisation of a given voltage transfer function by the use of this theorem is illustrated.     

Lossy transmission lines: time domain formulation and simulationmodel

The time domain quasi-TEM equations for lossy transmission lines with R, L, C, and G parameters is reformulated and solved to relate directly the currents and voltages at the line terminations, at present and past times. This allows a computer model to be set up for simulating circuits with nonlinear terminations in the time domain using general circuit simulators. This formulation describes propagation of two dynamic forward and backward waves and is the extension of the method of characteristics to the lossy case. Distortion and impedance changes are generated by finite convolutions with past history information at the line terminations. For constant R, L, C, and G, and for a skin effect approximation, the kernels of Green's functions for these convolutions are derived as analytic expressions     

Realisation of nth-order lowpass voltage transfer function by active R circuit: signal-flow-graph approach

A general synthesis method is given for the realisation of the nth-order lowpass voltage transfer function by the active R circuit containing n operational amplifiers and 4n resistors.     

New approach to aggregate model formulation through state feedback

Restrictions on the application of system aggregation methods are identified and related to rank deficiencies in the mapping of vector spaces. A state feedback technique is proposed that relaxes these limitations and allows useful reduced-order models to be formulated.     

Non-Wiener solutions for the LMS algorithm-a time domain approach

A time domain analysis of the LMS algorithm is presented for a sinusoidal deterministic reference input. For the sinusoidal reference input only, the N-dimensional time-varying linear matrix recursion for the weight vector is solved using a 2-D orthogonal subspace decomposition. Using this weight vector solution, it is shown that there exists a linear time-invariant relationship between the desired input and the filter output     

A simple approach to obtaining network state equations

A simple approach to obtaining the state equations for electric networks is introduced. This approach can easily accommodate any type of network element. It requires a relatively small number of simultaneous equations. An illustrative example is included.     

New wavelet based approach for time domain simulations

A new numerical method for the time domain solution of Maxwell's equations in linear media is proposed in this paper. The field quantities derived from the spatial discretization of Maxwell's equations are expanded in the time domain by wavelets on the interval. This choice yields a new arrangement of the unknowns into a matrix (instead of the usual vector) and transforms the differential equations in time in a Sylvester (1983) matrix equation. The memory requirements are proportional to the number of spatial unknowns and the time evolution of the space quantities is obtained with better accuracy than in conventional marching-on-time techniques.     

紧缩场干扰波的时域分析

紧缩场电气测试调整是保证紧缩场最终电气性能指标的一个重要过程。在此过程中，需要根据电气性能检测结果对紧缩场电气设计和机械设计进行必要的调整，排除或尽量控制影响静区的干扰波。在满足近轴近似的条件下，通过平面波角谱分析的方法可以准确地预测干扰波的入射方向和大小。对入射方向相同或相近的两列干扰波，可以采用时域分析方法进行辅助分析。     

The time domain Green's function and propagator for Maxwell's equations

The free space time domain propagator and corresponding dyadic Green's function for Maxwell's differential equations are derived in one-, two-, and three-dimensions using the propagator method. The propagator method reveals terms that contribute in the source region, which to our knowledge have not been previously reported in the literature. It is shown that these terms are necessary to satisfy the initial condition, that the convolution of the Green's function with the field must identically approach the initial field as the time interval approaches zero. It is also shown that without these terms, Huygen's principle cannot be satisfied. To illustrate the value of this Green's function two analytical examples are presented, that of a propagating plane wave and of a radiating point source. An accurate propagator is the key element in the time domain path integral formulation for the electromagnetic field.     

Direct GA-based optimisation of resistively loaded wire antennas inthe time domain

An optimisation procedure based on the genetic algorithm is applied to design resistively loaded wire antennas. The broadband characteristic of the antenna is realised through a maximisation of the fidelity factor directly in the time domain. The performance characteristics of the resulting antenna are presented and contrasted with those of the Wu-King design     

Blind identification and equalization based on second-orderstatistics: a time domain approach

A new blind channel identification and equalization method is proposed that exploits the cyclostationarity of oversampled communication signals to achieve identification and equalization of possibly nonminimum phase (multipath) channels without using training signals. Unlike most adaptive blind equalization methods for which the convergence properties are often problematic, the channel estimation algorithm proposed here is asymptotically ex-set. Moreover, since it is based on second-order statistics, the new approach may achieve equalization with fewer symbols than most techniques based only on higher-order statistics. Simulations have demonstrated promising performance of the proposed algorithm for the blind equalization of a three-ray multipath channel     

Mixed time/frequency domain approach to model reduction

The letter considers the problem of reducing the transfer function of a given system to a lower order. The approach proposed appears to be suitable in cases where both the frequency-domain and the time-domain characteristics of the given system are to be preserved in the reduced order model.     

High spatial order finite element method to solve Maxwell's equations in time domain

This paper presents a finite element method with high spatial order for solving the Maxwell equations in the time domain. In the first part, we provide the mathematical background of the method. Then, we discuss the advantages of the new scheme compared to a classical finite-difference time-domain (FDTD) method. Several examples show the advantages of using the new method for different kinds of problems. Comparisons in terms of accuracy and CPU time between this method, the FDTD and the finite-volume time-domain methods are given as well.     

基于时域法的单条形InP/InGaAsP-EAM调制器的行波电极的仿真与实验研究

行波电极(Traveling wave electrode,TW),是目前广泛采用的一种电极结构,可缩短光载波与调制信号的互作用长度,可有效避免分布电容(Contribution capacity,CR)对调制带宽的限制.基于时域法设计、分析了InP/InGaAsP-EAM调制器行波电极,并与实际制作的EAM的行波型TW进行了特征阻抗Zc、损耗系数α对比,结果表明用时域法设计、计算的TW的特征阻抗、损耗系数与实测的结果符合的较好,特征阻抗约为45Ω,在0～20 GHz的频率范围,损耗系数α小于4 dB/mm.     

An efficient approach to modeling of quasiplanar structures usingthe formulation of power conservation in spectral domain

An enhanced spectral domain approach (SDA) is developed for analysis of complex quasi-planar transmission lines. The method is based on a combination of the spectral domain formulation and power conservation theorem. The relationship between electric and magnetic fields is established inside dielectric layers by using the conventional SDA while the characteristic equation related to interface conditions is derived through the power conservation theorem. Maintaining the inherent advantages of the SDA, this technique is able to easily handle more complex quasi-planar structures. Generalized power formulation is also presented to calculate characteristic impedance. Convergence behavior is discussed considering the nature of power conservation. Various finlines with finite thickness of conductors are analyzed to demonstrate its applications     

A time domain approach for avoiding crosstalk in optical blockingmultistage interconnection networks

Crosstalk in multistage interconnection networks can be avoided by ensuring that a switch is not used by two connections simultaneously, in order to support crosstalk-free communications among N inputs and N outputs, a space domain approach dilates an N×N network into one that is essentially equivalent to a 2N×2N network. Path conflicts, however may still exist in dilated networks. This paper proposes a time domain approach for avoiding crosstalk. Such an approach can be regarded as “dilating” a network in time, instead of space. More specifically, the connections that need to use the same switch are established during different time slots. This way, path conflicts are automatically avoided. The time domain dilation is useful for overcoming the limits on the network size while utilizing the high bandwidth of optical interconnects. We study the set of permutations whose crosstalk-free connections can be established in just two time slots using the time domain approach. While the space domain approach trades hardware complexity for crosstalk-free communications, the time domain approach trades time complexity. We compare the proposed time domain to the space domain approach by analyzing the tradeoffs involved in these two approaches