基于LUT的SRAM-FPGA结构研究

作为微电子工业中发展最迅速的一个领域，现场可编程门阵列（FPGA）的内部结构设计越来越受到业内人士的关注。为此针对目前普遍采用的基于查找表（LUT）的SRAM－FPGA，着重研究了其逻辑模块设计、布线结构设计和输入输出模块设计，同时也对此类FPGA基本结构进行了优化设计。     

面向无线传感器网络的混沌加密与消息鉴别算法

针对数字混沌密码无法直接在轻量的传感节点上实现,介绍了一种基于整数型混沌映射的轻量级分组加密算法,并提出一种新型的消息鉴别码方案,具有输出长度可变、混沌序列复合安全等特点,最后实现了一个完整的无线传感网数据安全传输应用方案,并在Mica2节点上给出性能分析。实验表明该方案对无线传感网具有更高的实用性。     

新型全数字三相SPWM信号产生芯片的设计与实现

针对电力电子领域的需要,自行研制了一种新型三相正弦脉宽调制信号产生芯片.该芯片采用了改进的直接数字频率合成算法、流水线结构与ROM分时复用技术,保证了芯片的高性能和速度,节省了芯片面积.芯片系统时钟可达24MHz,输出信号的范围为DC到4kHz,精度为65536级,控制功能齐全.采用0.35μm COMS工艺流片,测试结果显示芯片达到设计指标.     

软交换网络集中监测系统SIP监测方案

结合对SIP(Session Initiation Protocol)协议的深入分析,采 用正则表达式匹配方式进行消息解码,着重分析SIP呼叫合成的算法,使用Hash技 术有效解决了CDR合成效率低下等关键难题。该方案在已商用的软交换集中监测系统中进行 了 测试和验证,效果良好。     

Enhancing quality of experience using peer‐to‐peer overlay on device‐to‐device communications

With the recent development of LTE‐A/5G technologies, data sharing among mobile devices offer an attractive opportunity to reduce Internet access. However, it requires smart strategies to share the data with low trade‐offs in time, cost, and energy. Several existing schemes offer a super‐peer‐based two‐tier model using a distributed hash table (DHT) organization for smart devices having device‐to‐device (D2D)/Bluetooth/WiFi capabilities. The primary focus of these schemes has been to reduce Internet usage by increased D2D content sharing. However, the real challenge is not in creating a two‐tier model, but evolving an efficient overlay that offers enhanced opportunities for D2D content sharing over the existing model. In this paper, we formulated a P‐median‐based selection of tier‐1 devices in a distribution network and solved it using the Lagrangian relaxation method. The tier‐2 devices become clients seeking content sharing services from tier‐1 devices. A strong motivation in this work is to raise a user's perception of the grade of service known as quality of experience (QoE). We analyzed the challenge for QoE assessment in resource‐constrained smartphones under the proposed model of enhanced D2D communication. Our focus is to establish a framework to evaluate QoE for applications and services over LTE‐A/5G networks with an improved D2D communication level. The simulation and the experimental results validate the claim that substantial improvements in QoE are possible with the proposed mathematical model for selecting and placing tier‐1 mobile devices and maintaining a DHT for D2D communication.     

Digital predistorter with improving index accuracy of lookup table based on FPGA

In this paper, a method of function approximation for improving index accuracy of the lookup table (LUT) of digital predistortion (DPD) is proposed to obtain more accurate linearization. The algorithm utilizes approximation of the LUT with the method of Taylor Series. The power values of forward signals are divided into integers and decimals, and the corresponding LUTs are indexed respectively. The index predistortion values of forward signals are approximated by Taylor series, which improves the index accuracy of LUT significantly. Experiment shows that the performance of a DPD system is improved.     

CDMA20001x EVDO网络MM4+协议监测的实现

首先对CDMA2000 1x EVDO网络中的增值业务进行了介绍,然后针对增值业务中不同网络间的多媒体消息互通问题,对关键接口MM4接口中的MM4+协议进行了介绍与监测.最后,借助哈希索引算法提出了一种新的CDR存储方案,并通过现网数据测试,验证了相关方法的可行性.     

A low-power direct digital frequency synthesiser

This work presents a low power direct digital frequency synthesiser (DDFS) by using a new two-level lookup table algorithm. The algorithm uses trigonometric double angle formula to divide lookup table ROM into two parts. The ROM size of the proposed architecture is 25% less than that of conventional lookup table DDFS. The hardware of new DDFS architecture compared to the traditional two-level table DDFS also requires less one multiplication. A synthesised 0.35 µm DDFS with an spurious free dynamic range of ?80 dB, runs up to 100 MHz and consumes 81 mW at 3.3 v. The power efficiency is 0.81 mW MHz^?1, which represents an enhancement of more than 38% compared to the conventional DDFS.     

一种新型多定子直线型超声电机的研究

直线型超声电机具有可直接驱动、精度高、响应快、适用于真空环境等优点，但驱动力较小。为提高工作台的负载能力，该文提出并研制了一种多定子直线型超声电机。样机由两个定子和一个动子(与工作台台面相联)组成。定子是一个利用1阶纵振和2阶弯振、带双足的兰杰文振子，双足交替驱动。讨论了该电机的驱动机理，对定子的结构进行了优化设计，给出了定子、动子、工作台一体化的设计方案，并对电机的输出性能做了初步的实验研究。     

基于ARID控制系统的固定式海洋风机纵摇控制

针对固定式海洋风机在随机风浪载荷及其联合作用下产生的具有倒立摆运动特征的纵摇,研究采用主动转动惯量驱动系统(Active Rotary Inertia Driver, ARID)对海洋风机纵摇进行控制的问题。ARID控制系统通过伺服电机驱动转动惯性质量产生控制结构摆动的最优力矩,从而减小海洋风机的纵摇运动。基于拉格朗日原理建立海洋风机-ARID控制系统的理论分析模型;采用Simulink对海洋风机-ARID控制系统的有效性进行验证,并分析系统参数(控制算法参数、转动惯量比等)对控制效果的影响规律;设计海洋风机-ARID控制系统的振动台试验,设置多种载荷激励形式,验证控制系统的稳定性与广谱有效性。数值模拟和试验结果均验证了所建立的分析模型的正确性,表明ARID控制系统对风机的纵摇运动具有显著的控制作用,为ARID控制系统在具有倒立摆运动规律的工程结构中的应用奠定理论基础。