Simplification of the Gram Matrix Eigenvalue Problem for Quadrature Amplitude Modulation Signals

In quantum information science, it is very important to solve the eigenvalue problem of the Gram matrix for quantum signals. This allows various quantities to be calculated, such as the error probability, mutual information, channel capacity, and the upper and lower bounds of the reliability function. Solving the eigenvalue problem also provides a matrix representation of quantum signals, which is useful for simulating quantum systems. In the case of symmetric signals, analytic solutions to the eigenvalue problem of the Gram matrix have been obtained, and efficient computations are possible. However, for asymmetric signals, there is no analytic solution and universal numerical algorithms that must be used, rendering the computations inefficient. Recently, we have shown that, for asymmetric signals such as amplitude-shift keying coherent-state signals, the Gram matrix eigenvalue problem can be simplified by exploiting its partial symmetry. In this paper, we clarify a method for simplifying the eigenvalue problem of the Gram matrix for quadrature amplitude modulation (QAM) signals, which are extremely important for applications in quantum communication and quantum ciphers. The results presented in this paper are applicable to ordinary QAM signals as well as modified QAM signals, which enhance the security of quantum cryptography.     

Efficient Systolic Array Mapping of FIR Filters Used in PAM-QAM Modulators

This paper presents efficient techniques for mapping FIR filter computation circuits for PAM and QAM modulators onto systolic arrays. The exploitation of the inherent symmetry of these problem instances and the use of Look-Up Tables (L.U.T.) in conjunction with the use of systolic architectures, increases the performance while keeping the VLSI area minimal. Exploiting parallelism and pipelining enhances the throughput and results in linear expandability of the FIR filter with respect to the bit accuracy and to the stage count.     

Capacity and Error Probability for Maximal Ratio Combining Reception over Correlated Nakagami Fading Channels

In this paper, the capacity and error probability of maximal ratio combining (MRC) reception are considered for different modulation schemes over correlated Nakagami fading channels. Based on an equivalent scalar additive white Gaussian noise (AWGN) channel, we derive the characteristic function (CF) and the probability density function (PDF) of the signal to noise ratio for MRC reception over Nakagami fading channels. Using these CF and PDF results, closed form error probability and capacity expressions are obtained for PSK, PAM and QAM modulation. Wei Li received his Ph.D. degree in Electrical and Computer Engineering from the University of Victoria in 2004. He is now a Post-doctoral Research Fellow in the Department of Electrical and Computer Engineering at the University of Victoria. He is a Member of the IEEE. His research interests include ultra-wideband system, spread spectrum communications, diversity for wireless communications, and cellular communication systems. Hao Zhang was born in Jiangsu, China, in 1975. He received his Bachelor Degree in Telecom Engineering and Industrial Management from Shanghai Jiaotong University, China in 1994, his MBA from New York Institute of Technology, USA in 2001, and his Ph.D. in Electrical and Computer Engineering from the University of Victoria, Canada in 2004. His research interests include ultra-wideband radio systems, MIMO wireless systems, and spectrum communications. From 1994 to 1997, he was the Assistant President of ICO(China) Global Communication Company. He was the Founder and CEO of Beijing Parco Co., Ltd. from 1998 to 2000. In 2000, he joined Microsoft Canada as a Software Engineer, and was Chief Engineer at Dream Access Information Technology, Canada from 2001 to 2002. He is currently an Adjunct Assistant Professor in the Department of Electrical and Computer Engineering at the University of Victoria. T. Aaron Gulliver received the Ph.D. degree in Electrical and Computer Engineering from the University of Victoria, Victoria, BC, Canada in 1989. From 1989 to 1991 he was employed as a Defence Scientist at Defence Research Establishment Ottawa, Ottawa, ON, Canada. He has held academic positions at Carleton University, Ottawa, and the University of Canterbury, Christchurch, New Zealand. He joined the University of Victoria in 1999 and is a Professor in the Department of Electrical and Computer Engineering. He is a Senior Member of the IEEE and a member of the Association of Professional Engineers of Ontario, Canada. In 2002, he became a Fellow of the Engineering Institute of Canada. His research interests include information theory and communication theory, algebraic coding theory, cryptography, construction of optimal codes, turbo codes, spread spectrum communications, space-time coding and ultra wideband communications.     

变速率QAM调制

本文采用ＤＳＰ芯片利用软件实现了对变速率ＱＡＭ基带信号的处理，变速率ＱＡＭ就是根据衰落的信道的传输特性来自发地调节信号的调制电平数，使信号的误码率在可以接受的条件下尽可能提高信息传道速率，仿真结果表明，在高信噪比情况下，保持同样的误码率，变速率ＱＡＭ的频谱利用率可以比４ＤＰＳＫ提高一倍以上。     

QAM接收机自动增益控制电路的设计

分析自动增益控制的原理,并提出一种应用于中频信号接收机的自动增益控制方案,本方案已经通过接收系统的测试,满足设计要求。     

数字电视的数字调制技术

本主要介绍数字有线电视网上、下行信道频谱的划分，各种数字调制方法、性能特点和优缺点比较。     

基于MPEGⅡ的机顶盒技术及其在视频点播中的应用

主要论述基于MPEGII的数字机顶盒技术及其在视频点播系统中的应用 ,包括机顶盒的相关协议标准、关键软硬件技术、具体的实现方法及其在VOD系统中的应用 ,并给出机顶盒技术的发展前景     

基于SystemView的16QAM调制解调系统的设计与仿真

正交幅度调制QAM（Quadrature Amplitude Modulation）以其高频谱利用率、高功率谱密度等优势，成为宽带无线接入和无线视频通信的重要技术方案。丈中介绍了QAM调制解调原理，提出了一种基于SystemView的16QAM系统调制解调方案，对16QAM系统的星座图和误码率进行了仿真。仿真结果证明该系统设计方案简易可行，对于QAM相关产品研发和QAM深入理论研究以及电子教学都具有一定的理论和实践指导意义。     

高性能数字电视QAM初始解调器的VLSI结构设计

本文设计了一种适用于高清晰数字电视（HDTV）接收芯片的全数字正交幅度（QAM）解调器结构。该解调器由数字混频器、数字频率合成器（DDFS）和低通滤波器构成。提出采用最佳平方逼近算法优化DDFS的输出正余弦波形，使得最差情况下的无杂散动态范围（SFDR）小于-75dBc。同时，对低通滤波器的实现方式采用了正交信号复用和系数扩展的方法，优化了滤波器结构，降低了所需电路的面积。     

有线数字电视射频信号调制识别研究

从有线数字电视射频信号特征参数提取着手,建立了一套识别16QAM和64QAM射频信号调制方式的数学算法。试验仿真和实际信号验证表明,该算法计算量小,识别率高,易于实现。本项研究为广播电视安全播出和数字电视终端整合提供有益的技术实践。