无线图传技术应用探讨

无线图传是无线图像传输系统的简称,是指不通过铺设线缆而是利用无线电波进行图像传输.常用的无线传输介质有微波、红外线、无线电波.近年来,随着相关技术设施日渐成熟,无线图传的画面质量和传输距离大幅度提高,被广泛应用于影视拍摄、视频监控及应急指挥等各个领域.围绕无线图传的技术类型、主要优点及影响因素等方面,探讨无线图传在视讯摄录方面的应用.     

我国无线数字电视系统的选择研究

无线数字电视技术探究 广义的无线数字电视包括利用现有标准传输的固定和移动数字电视、CMMB移动多媒体广播(手机电视)以及已经比较成熟的数字MMDS等各种利用无线信道传输的数字电视系统. 1.模型 按照传输理论, 一套电视广播体系包括播发、传输和接收.而无线数字电视区别于地面模拟电视的本质特征除信道的传输容量增大外,还支持移动接收.因此无线数字电视的技术体系有其自己的特点.     

BCMCS无线传输技术分析

本文针对BCMCS(广播与组播业务)技术标准,提出了BCMCS无线传输的技术要求,并通过分析其主要的无线传输技术,特别是差错控制技术、信道分配技术、高效传输技术和接收增强技术,说明其无线传输的技术特性.     

灾害性天气现场新闻报道无线设备研究和应用

有线连接方式的缺点在如今的灾害性天气直播报道中已经十分凸显,无线传输设备的引进改变了现有的设备连接方式.本文介绍灾害性天气现场报道的技术需求、无线传输设备功能及技术特点,以及其针对灾害性天气报道的技术贴合性和环境适应性.通过对设备的实际测试阐明了无线传输设备的应用效果.     

无线移动通信系统关键技术研究

无线移动通信系统已经得到了普及应用,如何提高无线信号传输的效率、提高天线接收效率等问题,将是未来一段时间内,人们研究的主要问题.本文在无线移动通信系统发展的基础上,结合我国自身的实际情况,从信号的处理和传输、多入多出技术、智能天线技术和传输协议等方面,对未来无线移动通信系统的关键技术,进行了深入的分析,希望能给实际无线移动通信系统的研究,提供一定的参考.     

基于云台的视频无线传输系统设计与应用研究

现阶段,无线通信技术和视频压缩技术都得到了快速发展和应用,无线视频传输成为了研究热点。目前的无线通信技术多种多样,包含蓝牙、无线局域网、Zigbee技术等,这些技术应用都能实现无线视频传输,对视频信息实施压缩编码。文中基于云台的视频无线传输系统设计及应用,为视频无线传输提供了一些思路和参考。     

60GHz毫米波无线通信技术标准综述

60 GHz无线通信技术可以提供数吉比特速率传输支持高清视频传输、快速同步、无线USB和高速无线局域网.毫米波标准包括了IEEE 802.15.3c、ECMA 387、IEEE 802.11ad、IEEE 802.11aj和中国CWPAN标准.主要介绍了我国毫米波标准、IEEE 802.11ad和IEEE 802.11aj标准及未来60 GHz无线技术.     

基于2.4G的无线音频传输系统

目前无线音频传输系统普遍存在传输带宽小、音质差等问题,鉴于此,提出一个基于2.4G的无线音频传输方案.该方案用达盛电子的UM2460作为无线收发器,同时使用新唐的NUC120作为MCU实验平台.实验测试表明2.4G无线音频传输技术不仅可行而且可以有效提高传输带宽,满足大数据量传输的要求.据此,展望了该技术在各方面的应用并提出几种可适用的场合,为无线音频传输产品的设计提供了一种新思路.     

无线光通信的传输和接入应用的若干思考

科学技术的发展推动无线光通信技术不断上升到新的高度和水平,其让信号的传授更加可靠,让人们的通讯生活更加便捷.在进行无线光通信技术发展的过程中,对其传输和接入进行研究尤为重要,这是提高无线光通信质量到重要路径.基于此,本文就无线光通信的传输和接入应用进行分析,以供参考.     

无线发射如何适应数字时代

随着数字时代的到来,无线发射技术被广泛应用起来.广播发射中的传输介质主要以光缆和无线技术为主,为了确保信号传输的稳定,技术人员可以通过发射技术有效控制信号.本文主要阐述无线发射技术在数字时代中的应用,综合分析无线发射技术的特点,并制定应用的具体策略,对相关技术人员进行培训,逐步提高技术人员的专业水平,从而满足现代化的发展需求.     

Non‐cooperative power control and spectrum allocation in cognitive radio networks: a game theoretic perspective

The invention of cognitive radio (CR) concept aims to overcome the spectral scarcity issues of emerging radio systems by exploiting under‐utilization of licensed spectrum. Determining how to allocate unused frequency bands among CR is one of the most important problems in CR networks. Because different CRs may have different quality‐of‐service requirements, they may have different objectives. In voice communication, high‐speed transmission is the most important factor; hence, voice radios always try to maximize their transmission rate. However, in data communication, the most important factor is the bit error rate. The data radios always try to maximize their signal‐to‐interference‐plus‐noise ratio (SINR). In this paper, two non‐cooperative games named interference minimization game and capacity maximization game, which reflect the target of data radios and voice radios, respectively, are proposed. From the simulations, after these games are applied, the average SINRs of all players at each channel are improved. The average SINR of players in each channel after applying the capacity maximization game is smaller than that after applying the interference minimization game. However, in comparison with that after applying the interference minimization game, the average capacity of players after applying capacity maximization approach is larger. Copyright © 2012 John Wiley & Sons, Ltd.     

DRM博弈控制分析

提出了一种博弈控制模型。博弈的控制者是全局理性的,并依据控制目标来选择策略,迫使被控者依据个体理性原则选择控制者期望的策略,从而实现全局的优化控制。在此基础上,分析了DRM价值链实体的关系和行为,建立了DRM博弈控制模型,讨论了内容提供商如何作为博弈的控制者选择全局优化策略,以实现和用户之间稳定的互利共赢,为DRM的合理应用提供了理论指导。     

一种自动测试游戏机手柄芯片的设计与实现

游戏机手柄芯片的测试一直以来总是采用人工依次测试测点的方法,这种方法费时费力,难以满足批量生产的要求。本文介绍了一种测试游戏机手柄芯片的新方法,以游戏机手柄芯片E2749为例,用单片机实现芯片的自动测试。实践证明,这种方法原理简单,可移植性强,可广泛运用到各类芯片的测试中。     

Simultaneous spectrum sensing,data transmission and Energy harvesting in multi‐channel cognitive sensor Networks with imperfect signal cancellation

In multichannel cognitive sensor networks, the sensor users which have limited energy budgets sense the spectrum to determine the activity of the primary user. If the spectrum is idle, the sensor user can access the licensed spectrum. However, during the spectrum sensing, no data transmits. For improving the network throughput and saving more energy consumption, we propose the simultaneous spectrum sensing and data transmission scheme where the sensor receiver decodes the received signal, and from the remaining signal, the status of the channel (idle/busy) is determined. We also consider that the sensor users are powered by a radio‐frequency (RF) energy harvester. In this case, energy harvesting, data transmission, and spectrum sensing are done simultaneously. On the other hand, we select the proper sensor users for spectrum sensing and energy harvesting. We also allocate the best channels for data transmission simultaneously so that the network throughput maximizes and the constraints on the energy consumption and the detection performance are satisfied for each band. We formulate the problem and model it as a coalition game in which sensors act as game players and decide to make coalitions. Each coalition selects one of the channels to sense and transmit data, while the necessary detection probability and false alarm probability and also the energy consumption constraints are satisfied. The utility function of a coalition is proposed based on the energy consumption, false alarm probability, detection probability, and the network throughput. This paper proposes an efficient algorithm to reach a Nash‐stable coalition structure. It is demonstrated that the proposed method maximizes the network throughput and reduces the energy consumption while it provides sufficient detection quality, in comparison to other existent methods.     

基于博弈的协作路由算法

协作虚拟多输入多输出（VMIMO）传输是一种有效的无线传输性能优化技术。将物理层协作VMIMO技术和网络层路由选择技术相结合,设计跨层VMIMO路由选择方案可以利用VMIMO的分集增益,显著地降低网络传输能耗。如何设计VMIMO协作路由协议抵抗无线网络的自私节点和欺骗行为,保证高数据转发率和低传输能耗成为路由设计中的重大挑战。为了提高自私网络的VMIMO路由性能,提出了一种基于重复路由博弈的VMIMO协作路由算法。该算法将网络划分成多个Group、Group间使用VMIMO传输数据。将Group间路由选择过程建模为重复路由博弈过程。为了提高数据转发的成功率,提出适用度函数评估节点参与数据分组转发的信誉。以此为基础,提出基于适用度的路由选择子算法和路由转发子算法。理论证明所提重复路由博弈可达到帕累托最优。仿真实验结果表明本算法可以促进自私节点相互合作,可获得较高的数据转发率,较好地减少数据传输时延以及能量消耗。     

Comparative analysis of fixed and sinusoidal band hysteresiscurrent controllers for voltage source inverters

A hysteresis controller with a sinusoidal band for current regulation is described. The behavior of the conventional fixed-band controller and the proposed sinusoidal band controller has been thoroughly studied. Simulation results demonstrate that with no lockout (permitting a very high switching frequency) the current waveform can be confined within the desired hysteresis bands. At low lockout frequencies the current is not confined within the hysteresis bands and both fixed and sinusoidal band controllers give a high ripple. The study also shows that with a reasonable lockout frequency, a sinusoidal band control results in a reduced ripple and lower harmonic content. However, the switching frequency is higher with the sinusoidal bands. This should not be a major concern with the availability of fast switching devices that allow higher lockout frequencies     

部分无序二维光子晶体透射特性研究

用时域有限差分法研究了光在部分无序二维光子晶体中的透射特性。结果表明：介质柱的位置和大小无序都对光子晶体的高频透射特性都有影响而对低频几乎无影响,随着无序度增大,禁带呈现拓宽的趋势。仅介质柱的位置无序变化时,每个带隙低频端边缘比高频端边缘对无序度变化更敏感。仅介质柱的大小无序变化时,每个带隙间的通带频率越高对无序度变化越敏感。介质柱的大小无序和位置无序度相同时,在高频段后者比前者作用更显著。     

传输线变压器相位补偿技术及其应用

传输线变压器是在短波和超短波频段使用广泛的重要器件,根据传输线变压器原理设计制造的器件具有结构紧凑、功率容量大、频带宽、损耗小等优点.该文研究了利用慢波线原理和相位补偿技术克服传输线变压器对于传输线电长度的限制,使其适用频率向s波段以上扩展的方法.文中给出了1:4阻抗变换器电路的传输损耗和高低端输入阻抗理论公式并对其进行了讨论.对所设计的S波段1:4阻抗变换器及功率合成器进行了仿真分析并设计制作了实物.仿真和实测结果表明,利用慢波线原理和相位补偿后的传输线变压器能够适用s波段及以上微波器件.     

Polarization-independent frequency-selective rasorber with a broadened absorption band

A polarization-independent frequency selective rasorber (FSR) with a transmission band at high frequency and a broadened absorption band at low frequency is designed and analyzed in this paper. The FSR consists of a resistive sheet and a bandpass frequency selective surface (FSS). A strip-type micro resonator (MR) is developed and applied in the resistive element. The MR is equivalent to a parallel LC circuit and resonates at the transmission band. The induced surface current distributions on the resistive element at different frequencies can be controlled as expected using the MRs, so that a high in-band transmission at high frequency and an absorption band at low frequency can be obtained, which are almost independent to each other. The absorption bandwidth can be broadened by cascading more MRs with several resistor-loaded metallic strips. Besides, due to the tiny dimensions of the MRs, polarization-independent absorptive/transmissive performances can be achieved by printing two orthogonal arrays of resistive elements on different surfaces of a dielectric substrate. The performance of the FSR is verified by both numerical simulation and experimental measurement.     

十字型结构声子晶体带隙及等效模型研究

该文设计了一种新型十字型声子晶体结构,并采用有限元法对其进行了研究;分析了此结构若干共振频率下的振动模态,分别建立了带隙起始频率与截止频率处振动模态的简化模型,探究了结构与材料参数对带隙的影响,验证了简化模型的合理性;最后计算了结构的反射系数与透射系数。结果表明,该结构带隙产生机理属局域共振型,能够在中低频段内产生一个完全带隙。通过对金属芯体密度、基体密度、包覆层的宽度及弹性模量等因素的调节,可以实现对带隙上、下界频率的调节,结构的反射系数与透射系数随入射波频率的变化也与带隙图相应证,当带隙图显示出现带隙时,结构的透射系数也随之下降。