应用Gauss积分法计算STO双中心重叠积分

本文将Gauss求积法引进STO双中心重叠积分的计算中.结果表明此法计算简便快速,具有相当高的精确度,并大大地扩展了STO双中心重叠积分的适用范围。     

INTERPOLATORY QUADRATURE RULE FOR EVALUATION OF CERTAIN SINGULAR INTEGRALS

In this paper, we introduce a quadrature rule for the numerical evaluation of certain hyper singular integrals. The rule is obtained by using Hermite interpolation polynomial. Error bound is also made.     

Generalization of differential quadrature discretization

The differential quadrature (DQ) is generalized. Various methods for generating the weighting coefficients are developed. The design of a grid model is flexible. Weighting coefficients for general multi-coordinate grid models with arbitrary configurations can also be calculated. The calculation of weighting coefficients is easy. Sample numerical procedures for constructing one-coordinate, two-coordinate and arbitrary finite-coordinate generic differential quadrature models are presented. This revised version was published online in June 2006 with corrections to the Cover Date.     

Differential Quadrature Analysis of Moving Load Problems

The differential quadrature method (DQM) has been successfully used in a variety of fields. Similar to the conventional point discrete methods such as the collocation method and finite difference method, however, the DQM has some difficulty in dealing with singular functions like the Dirac-delta function. In this paper, two modifications are introduced to overcome the difficulty encountered in solving differential equations with Dirac-delta functions by using the DQM. The moving point load is work-equivalent to loads applied at all grid points and the governing equation is numerically integrated before it is discretized in terms of the differential quadrature. With these modifications, static behavior and forced vibration of beams under a stationary or a moving point load are successfully analyzed by directly using the DQM. It is demonstrated that the modified DQM can yield very accurate solutions. The compactness and computational efficiency of the DQM are retained in solving the partial differential equations with a time dependent Dirac-delta function.     

轴向运动粘弹性板的横向振动特性

研究了轴向运动粘弹性矩形薄板的动力特性和稳定性问题．从二维粘弹性微分型本构关系出发,建立了轴向运动粘弹性板的运动微分方程．采用微分求积法,对四边简支、一对边简支一对边固支两种边界条件下粘弹性板的无量纲复频率进行了数值计算．分析了薄板的长宽比、无量纲运动速度及材料的无量纲延滞时间对其横向振动及稳定性的影响．     

Current‐mode quadrature oscillator using current differencing transconductance amplifiers

This article presents a new electronically tunable single‐element‐controlled current‐mode quadrature sinusoidal oscillator circuit using current differencing transconductance amplifiers (CDTAs). The proposed oscillator is consisted of two CDTAs, two grounded capacitors and one grounded resistor, which is beneficial to monolithic integrated circuit implementation both in CMOS and bipolar technologies. The condition of oscillation and the frequency of oscillation are independently controllable. The frequency of oscillation can also be electronically controlled by adjusting the bias current of CDTA. The circuit provides four quadrature current outputs and two quadrature voltage outputs. The current output terminals possess high impedance level. PSPICE simulation results are used to verify the performance of the proposed circuit implemented at the transistor level. The measurement results support the computer simulations.     

Bottom-series coupled quadrature VCO using the inductive gate voltage boosting technique

This article presents a new low-voltage bottom-series coupled quadrature voltage-controlled oscillator (QVCO), which consists of two n-core cross-coupled VCOs with the bottom-series coupling transistors. The low-voltage operation is obtained via an inductive gate voltage boosting technique. The proposed CMOS QVCO has been implemented with the TSMC 0.18?µm CMOS technology and the die area is 0.897?×?0.767?mm². At the supply voltage of 0.7?V, the total power consumption is 1.5?mW. The free-running frequency of the QVCO is tuneable from 3.77 to 4.12?GHz as the tuning voltage is varied from 0.0 to 0.7?V. The measured phase noise at 1?MHz frequency offset is ?123.35?dBc/Hz at the oscillation frequency of 4.12?GHz and the figure of merit of the proposed QVCO is ?193.5?dBc/Hz.     

100Gb/s RZ-ODQPSK实现方法性能比较

光差分正交移相键控(0DQPSK)调制格式在高速光纤通信系统中有着巨大的应用潜力.文章给出了高速0DQPSK调制格式的三种实现方式(串联调制、并联调制和双驱动单调制器调制),在建立仿真模型的基础上,对光信噪比(0SNR)、色散、偏振模色散(PMD)以及光纤非线性四个方面的容纳能力进行了对比、分析和研究.     

复合k-m/Gamma衰落信道下的平均信道容量

A new analytical expression is presented for the instantaneous power Probability Density Function (PDF) of receiver signals over composite κ-μ/gamma fading channels. Moreover, the exact expression of channel capacity is derived in the form of an infinite series, while an accurate approximation expression is obtained in closed form. To reveal the implications of the model parameters on capacity, we provide an expression for the case of a high-SNR environment. The relationship of the presented results with previously reported results on generalised-K and K fading chan-nels is also discussed. Finally, numerical and simulation results are presented to prove the correctness of our derived expressions.     

超高速光通信的新技术及应用

介绍了40 Gbit/s、100 Gbit/s及以上速率超高速光通信中将会用到的新技术,包括相位调制、正交幅度调制、多电平调制等新型调制技术,偏振复用和正交频分复用等新型复用技术,相干接收技术,光子集成技术。最后介绍了这些新技术在400 Gbit/s、1 Tbit/s等超高速光通信上的应用以及超高速光通信方面的研究进展,实现了1 Tbit/s速率下CO-OFDM 1 040 km的普通单模光纤的无误码传输。