基于DCT正交基的相位噪声均衡法

相位噪声是困扰OFDM通信系统的问题之一，它会破坏系统子载波之间的正交性，从而引起载波间干扰（ICI），降低系统性能。为此，提出一种时域的相位噪声均衡算法。仿真结果表明它具有良好的性能。     

WDM系统中级联EDFA的自动增益控制

综合分析了WDM系统中掺铒光纤放大器(EDFA)的主要性能指标，以及内外部工作条件的关系，讨论了有关EDFA的动态增益锁定与平坦机制。提出了更加优化的WDM系统中EDFA的自动增益控制的解决方案，并设计相关了试验，给出了采用本方案实现EDFA动态增益控制的分析结果。最后，指出了各种科技产品的问世，为EDFA的自动增益控制研究提供了更加广阔的思路和便利的条件。     

严重椒盐噪声污染图像的非线性滤波算法

针对灰度图像的椒盐噪声滤波问题，提出一种保细节的非线性滤波算法。利用局部统计信息，首先将图像像素点粗分为信号点、可能的正噪声点和可能的负噪声点3类，建立噪声标矩阵；然后再根据噪声标记矩阵的局部统计信息，将可能的噪声点细分为信号点、噪声点和不确定点3种类别，并分别采用不同的方法进行滤波，以保留更多的图像细节。结果表明，本文算法在去噪能力、自适应性以及保留细节等方面都明显比其它4种算法强，尤其是对于噪声高度污染图像的情况。     

2.5GHz低相位噪声CMOS LC VCO的设计

用0 .35μm、一层多晶、四层金属、3.3V的标准全数字CMOS工艺设计了一个全集成的2 .5 GHz L C VCO,电路采用全差分互补负跨导结构以降低电路功耗和减少器件1/ f噪声的影响.为了减少高频噪声的影响,采用了在片L C滤波技术.可变电容采用增强型MOS可变电容,取得了2 3%的频率调节范围.采用单个16边形的对称片上螺旋电感,并在电感下加接地屏蔽层,从而减少芯片面积,优化Q值.取得了在离中心频率1MHz处- 118d Bc/ Hz的相位噪声性能.电源电压为3.3V时的功耗为4 m A.     

Analysis and Optimization of Noise in Bipolar RF Harmonic Mixers

A noise analysis of bipolar harmonic mixers (BHM) used for direct-conversion receivers is presented in this paper. Analytical and simulated results for the transfer function of the mixer are presented. Simple analytical expressions describing noise contribution from all sources are derived. Estimation of flicker noise quite agrees with harmonic-balance simulation results. Based on the derived expressions, total time average noise power spectral density (PSD) at the output is compared with simulation results. For the recommended regions of operation, error is less than 20%. The overall BHM noise figure (NF) is calculated and optimized based on a simple extracted formula. Errors introduced by analysis remain within a 1.5-dB margin with respect to simulation results. The validity of analysis for high frequencies is justified. The effect of flicker noise coefficient on the overall mixer NF is compared for different available processes.     

太赫兹光非对称解复用器中自发辐射噪声特性分析

提出了一个在超短脉冲注入半导体光放大器 (SOA)时 ,在考虑了半导体带间效应以及带内效应 ,包括载流子热效应、谱烧孔效应、双光子吸收效应以及超快非线性折射效应的自发辐射噪声的计算模型。并利用该模型计算了放大自发辐射 (ASE)噪声对太赫兹光非对称解复用器 (TOAD)开关性能的影响。数值结果表明 ,在考虑ASE噪声情况下 ,TOAD的开关窗口的边沿更陡 ,在开关窗口的尾部还会出现明显的小峰。结果还表明 ,在输入为理想孤子脉冲下 ,即使考虑ASE噪声 ,在TOAD处于开的状态时 ,其输出信号的信噪比也大于 2 5dB。     

ANALYSIS OF INTERNALLY GENERATED NOISE OF BIOELECTRIC AMPLIFIERS

This papenr deals with internally generated noise of bioelectric amplifiers that are usually used for processing of bioelectric events.The main purpose of this paper is to present a procedure for analysis of the effects of internal noise generated by the active circuits and to evaluate the output noise of the author‘s new designed bioelectric amplifier that caused by internal effects to the amplifier circuit itself in order to compare it with the noise generated by conventional amplifiers.The obtained analysis results of internally generated noise showed that the total output noise of bioelectric active circuits does not increase when some of their resitors have a larger value.This behavior is caused by the different transfer functions for the signal and the respective noise sources associated with these resistors.Moreover,the new designed bioelectric amplifier haws an output noise less than that for conventional amplifiers.The obtained analysis results were also experimentally verified and the final conclusions were drawn.     

空域红外图像的背景噪声分析及预处理

文中就如何提高空域背景下弱小目标的信噪比问题展开讨论，基于对背景噪声的统计分析提出了自适应滤波和小波分析两种图像预处理算法，达到抑制背景噪声，增强小目标的目的，并将二者进行了性能分析。     

二维小波去噪在太阳射电数据处理中的应用

针对太阳射电数据的处理问题，对数据所含噪声，可以通过小波分解高频系数可以估计出其噪声强度。本文主要探讨二维小波方法在有关射电天文观测的数据消除噪声研究中的应用。     

PD雷达欺骗干扰方法浅析

概要介绍了PD雷达的抗干扰性能及其特点．并主要对PD雷达的欺骗干扰方法进行了一定的讨论。