Effects of cross-phase modulation in wavelength-multiplexed SCMvideo transmission systems

Channel crosstalk effects in wavelength-multiplexed subcarrier-multiplexing video transmission systems due to cross-phase modulation are investigated. The crosstalk level depends on the spacing of optical channels. For analogue CATV transmissions in the 1.5 μm window using normal singlemode fibre, it is shown that the number of achievable optical channels is severely limited by cross-phase modulation for typical system parameters     

T_C≥400°C高温PTC陶瓷的研制

利用国产原料，采用传统的陶瓷材料制备工艺，研制了居里温度ＴＣ≥４００°Ｃ的高温ＰＴＣ陶瓷，制成了居里温度ＴＣ＝４１２°Ｃ，电阻Ｒ≤１０３Ω，ｌｇ（Ｒｍａｘ／Ｒｍｉｎ）＝４的高性能ＰＴＣ热敏陶瓷材料     

Dynamic oxide voltage relaxation spectroscopy

A new method for trap characterization of oxidized silicon is described. The Dynamic Oxide Voltage Relaxation Spectroscopy (DOVRS) is an improved version of the formerly proposed Oxide Voltage Relaxation Spectroscopy (OVRS) technique which applies a periodic long duration constant current for tunneling injection. It has been demonstrated that the new technique can be used not only to separate and identify the oxide trap from interface trap, but also to separate and determine the centroid from the oxide trap density generated in the MOS system by the tunneling current stress. In the pulse constant current mode, the OVRS measurement can be completed instead of using the double current-voltage technique. Thus the new method results in more accurate and quicker measurements of the oxide trap centroid. Analytical expressions for computing the paramaters of the interface and oxide traps are derived. The effect of the channel carrier mobility on the spectroscopy is also considered. Two types of oxide and two types of interface traps were observed at a pulse constant Fowler-Nordheim current stress by the new method of DOVRS     

最大度为6的极大外平面图的完备色数

证明了最大度为６的极大外平面图的完备色数为７。     

Transient hot-electron effect and its impact on circuit reliability

Transient hot-electron effect and its impact on circuit reliability are investigated. The rate of device decay is monitored as a function of the gate pulse transient period. Simulation results reveal that excess charges during a fast turn off time may cause an increase in the maximum substrate current. This, along with our experimental data, identifies that transient excess carrier may cause the enhancement of device degradation under certain stress conditions. The enhancement factor of the degradation is a function of the gate pulse transient time. Correlation between the analysis based upon AC/DC measurement and calculations based upon transient simulation are shown in the paper. Better agreement with experimental data is obtained by using the transient analysis and on chip test/stress structures. The correlation between AC and DC stress data is also shown based on the impact ionization model. A hot-electron design guideline is proposed based on the circuit reliability analysis. This guideline can help improve the circuit reliability without adversely effecting the circuit performance.     

Robustly good trellis codes

The relationship between the distance properties of trellis codes and the computational effort and error performance of sequential decoding is studied and optimum distance profile (ODP) and optimum free distance (OFD) trellis codes are constructed for 8-PSK and 16 QAM modulation. A comparison of the performance of both the ODP and the OFD trellis codes reveals that neither class of codes results in the best trade-off between error performance and computational effort when sequential decoding is used. A new algorithm is then proposed to construct robustly good trellis codes for use with sequential decoding. New trellis codes with asymptotic coding gains up to 6.66 dB are obtained using this algorithm, and the new codes achieve nearly the same free distances as the OFD codes and nearly the same distance profiles as the ODP codes     

Low-voltage BiCMOS dynamic minimum circuit using a parallelcomparison algorithm for fuzzy controllers

The authors present a low-voltage BiCMOS dynamic minimum circuit using a parallel comparison algorithm for VLSI implementation of fuzzy controllers. Using low-voltage BiCMOS dynamic circuits and a parallel comparison algorithm, a four-4-bit-input minimum circuit designed, based on a 1μm BiCMOS technology, shows a 9.5ns comparison time, which is a ×2.5 improvement in speed as compared to that based on CMOS technology     

新型蓝绿发光材料ZnSe／BeTe超晶格的能带剪裁

由于器件的快速退化，101.5小时似乎成了Znse基蓝绿色半导体激光器难于逾越的寿命极限。分析退化机制，发现在强电流注入的半导体激光器中，热退化具有重要影响。研究表明，用作载流子限制层的宽带Ⅱ-Ⅵ族四元合金（如ZnMgSSe）只能对ZnSe中的电子有效地限制，无法对空穴很好地限制;而对BeTe，却只能对空穴进行有效的限制，无法对电子很好地限制。这导致ZnSe（或BeTe）活性层空穴（或电子）漏电发热，引起退化。本文提出以ZnSe／BeTe超晶格为蓝绿发光层，并用包络函数理论具体计算了阱宽、垒宽对载流子能级的不同影响，考察了ZnSe、BeTe厚度比和超晶格周期对带隙、载流子限制能力的调节。为研制新型长寿命蓝绿色半导体激光器提供了一条新的途径。     

网络分解法的误差分析

网络分解法是求解电大尺寸复杂结构电磁问题的重要方法之一,关于网络分解法误差分析的研究有着重要的理论意义和实用价值.本文给出了网络分解法的误差估计,并对于脉冲基函数转换成三角基函数的情况给出了三角基函数个数的最优公式,数值结果表明了分析的正确性.     

集群系统与公用网互连的仿真模型和模拟算法

在讨论ＭＰＴ１３２７信令的集群移动通信系统与国内Ｎｏ．７信令的ＰＳＴＮ网间互连，帝现两种信令配合中，研究了集群系统的仿真模型和模拟算法，同时模拟出整个集群系统的工作情况，运行结果证实了所提方案的可行性与准确性。