Design of Down-Sampling Processors for Radio Communications

This paper deals with design and implementation of digital filter processors to be used as down-samplers in wireless transceivers. We consider a homodyne direct conversion and propose an improved method to specify each stage of the cascade structure. The proposed scheme results in a globally compact implementation. The method is detailed for DECT standard and illustrated by a fixed point FPGA based implementation.     

光收发模块眼图、消光比及灵敏度关系的实验研究

光接收灵敏度与光发射信号的消光比大小和眼图的上升沿/下降沿陡度具有紧密相关性，试验研究表明，155Mbps光收发模块消光比在16-20dB之间时光接收灵敏度最佳，眼图的上升沿/下降沿陡度越陡越好，一般情况下随上升沿/下降沿陡度的变化光接收灵敏度具有2-3dB的差异。     

基于滤波和平方的前馈式定时误差检测算法比较

介绍了三种基于滤波和平方的前馈式定时误差检测算法，比较了它们的结构和计算复杂度，并以QPSK信号为例建立了MATLAB仿真模型，比较了它们的检测性能，包括S曲线和定时估计方差，从中得出了一些有益的结论。     

Smoothing Streams in an In-Home Digital Network: Optimization of Bus and Buffer Usage

In an in-home digital network it may be expected that several data streams (audio, video) run simultaneously over a shared communication device, e.g., a bus. The burstiness of a data stream can be reduced by buffering data at the sending and receiving side, thereby allowing a lower bus share allocation for the stream. In this paper we present an algorithm that determines how much of the bus capacity and buffer space should be allocated to each stream, in order to have a feasible transmission schedule for each stream. Furthermore, the algorithm determines a transmission schedule for each stream, indicating how much data is transmitted over time. We show how this multiple-stream problem can be solved by repeatedly solving single-stream problems. We present efficient algorithms to solve these single-stream problems. Furthermore, we present some experimental results. This revised version was published online in September 2006 with corrections to the Cover Date.     

一种基于ICA的图像水印方法

本文提出了一种结合离散小波变换(DWT)、离散余弦变换(DCT)和独立分量分析(ICA)的图像数字水印方法。该方法把原始图像进行二维小波分解，保留其高频细节信息，然后对小波逼近子图进行离散余弦变换并嵌入水印。水印的检测使用了ICA方法。实验结果表明该水印方案很好的实现了水印的鲁棒性与不可见性的统一，对各种攻击具有很好的鲁棒性。同时由于ICA方法的引入，较好的改善了水印的检测效果。     

Design for 2-D error feedback networks with identical coefficient sets

In realization of recursive digital filters with fixed point arithmetic, an error caused by roundoff arises. It is known that the level of the roundoff noise of an IIR filter tends to be high when the poles are close to the unit circle. Error feedback (EF) is an effective method to reduce the roundoff noise. It is desirable to design an EF network using as few parameters as possible in order to keep computational costs low. In this paper, we propose a method for designing a 2D EF network with identical coefficient sets. That is, the EF coefficients are divided into several subsets such that all the elements within each set have the same absolute value. In order to optimize the coefficient sets, we propose an algorithm by using the genetic algorithm. In the numerical example, we demonstrate the effectiveness of the proposed method.     

数字水准仪的数据采集与数据处理系统研究

介绍了数字水准仪数据采集系统的原理与设计。以及数据处理的方法。该数据采集系统硬件电路简单、设计成本低、使用方便。数据处理算法采用一维边缘检测算子的递归算子提取标尺条码边缘，大大降低了数据处理的运算量，提高了运算速度。实践证明了该方案的可行性。     

ADS7864在电网数据采集中的应用

介绍了一种高速，低功耗，6通道双12位A／D转换器ADS7864及其用在电网数据采集中的应用。     

一种低成本工程卫星接收机的设计

介绍了一种在有线电视前端系统中的低成本卫星接收机的方案，分析了其可行性，介绍了硬件系统结构、软件流程，并以实时状态检测为例，详述了任务并行的实现，还着重介绍串口管理功能模块的实现。     

基于软件无线电的相控阵雷达系统研究

主要论述了相控阵雷达系统中软件无线电的实现结构，首先从软件无线电的概念出发，论述了在相控阵雷达系统中采用软件无线电技术的必要性和可能性；其次详细地论述了相控阵雷达系统中软件无线电的实现形式：即天线子系统、收/发子系统、信号处理子系统。最后对软件无线电技术在现代雷达中的发展进行了展望。