ROTATED BARNES-WALL LATTICE BASED VECTOR QUANTIZER AND ITS APPLICATION IN IMAGE-SEQUENCE CODING

A new scheme is presented to design a rotated Barnes-Wall lattice based vector quantizer(LVQ). The construction method of the LVQ and its fast quantizing algorithm are described at first. Then gain-shape lattice vector quantizer(GSLVQ) with LVQ as shape quantizer is discussed. Finally the GSLVQ is used in image-sequence coding and good experimental results are obtained.     

圆形有源介质F－P腔的横模分析

利用有源增益薄片近似代替有源腔中的增益介质和采用Ｆｏｘ－Ｌｉ迭代法，我们获得了微型ＤＰＬ的圆形有源介质Ｆ－Ｐ腔的模模模型，同时还分析了腔稳态场的振幅和相位分布分别受腔的菲涅耳数Ｎ和非饱和增益增量△Ｇ影响的情况。数值计算结果与文献报道的实验情况比较一致。     

利用子波变换检测瞬时信号

本文提出一种基于子波变换的检测瞬时信号的方法。推导出一种适合于检测瞬时信号的子波基函数，并将其应用于检测波形和到达时间未知的瞬时信号，利用子波的伸缩和时移特性，通过对信号做多尺度的子波变换，可以在低信噪比下很好地检测到信号，本文还推导了相应的检测统计量及其统计分布特性，理论分析和计算机模拟结果表明，本方法是有效的，是提高检测性能的一种新途径。     

M－QAM系统中载波相位估计量的统计特性分析

本文提出循环类分解和等模类分解法，解决了Ｍ－ＱＡＭ系统中载波相位估计量［１］的统计分析问题。证明了载波相位估计方差除了与加性噪声有关外，它与载波归一化频差的平方成正比；与码型噪声有关，同时，本文的结果简化了对码型噪声的分析模型。     

GaAs数字电路输入输出接口电路的设计

本文讨论了ＧａＡｓ电路和ＳｉＥＣＬ电路的输入输出接口问题，对ＧａＡｓ电路中ＢＦＬ、ＤＣＦＬ、ＳＤＦＬ等电路形式的典型输入输出接口电路进行了分析研究，用电路模拟程序计算并给出了ＢＦＬ输入输出接口电路的转移特性曲线。     

波导中入射脉冲的重建

本文用时域有限差分算法给出了波导中入射场的重建方法，研究了波导中脉冲传播的吸收边界条件。用本文的方法，只要测量出波导出口面上任一位置的场随时间的变化曲线，即可实现入射场的精确重建。     

多层介质光学膜系的误差分析——膜层厚度变化的灵敏度因子

文中推导了对于给定膜系的特定膜层的厚度变化的灵敏度因子计算公式，并给出了用计算机对不同膜系的计算实例。分析了厚度灵敏度因子对膜系透射光谱的灵敏谱段、灵敏膜层等特性的影响规律，并由此给出了确定膜层厚度允差的方法。     

On location management for personal communications networks

Personal communications services (PCS) support mobile terminals (MTs) which are free to travel within the service coverage area. In order to effectively locate an MT when a called is initiated, location management schemes are used to keep track of the locations of the MTs. The current approach to location management requires each MT to report its location to the network periodically. The location information is then stored in databases. When a call is initiated. The network determines the current location of the called MT through a database lookup and paging procedure. A currently available standard for location management is described. Research results on location management are surveyed in detail     

Optimal predistortion of Gaussian inputs for clipping channels

For a clipped channel with a Gaussian input, a predistortion/restoration technique to reduce clipping-induced nonlinear distortion is proposed and analyzed. The input signal is processed by a nonlinear predistorter circuit, reducing the probability of clipping. The receiver output signal passes through a restorer having an inverse transfer characteristic, which yields the original signal. For both one-sided and two-sided limiter channels, the optimal predistortion curves are determined analytically. A limiter channel with Gaussian input may be used to model clipping-induced nonlinear distortion in optical-fiber common antenna television (CATV) distribution systems using multiple intensity-modulated subcarriers. When applied to an amplitude-modulated vestigial-sideband (AM-VSB) CATV system, the optimal predistortion curves yield sensitivity improvements of 5.3 and 4.4 dB for oneand two-sided limiter channels, respectively     

强度调制／直接检测（IM／DD）光纤通信系统的色散限制

本文讨论了光纤色散对ＩＭ／ＤＤ光纤通信系统再生中继距离的限制，导出了适用于各种眼图恶化量、归一化脉宽和光源线宽展宽因子，且便于工程计算的Ｂ２Ｌ表达式。通过与其它理论的比较、计算机仿真研究和对实际系统实验数据的分析，说明了该公式所得结论的正确性以及其它结果的限制条件。