宽带网络电台波形技术研究

介绍了宽带网络电台的研究进展,提出了一种宽带网络电台的波形设计方案。实现了基带信号波形的发妙接收实验系统,并对OFDM调制解调技术、同步技术、信道估计及峰均比抑制技术进行了研究与仿真,实验结果表明文章提出的波形技术具有良好性能与实用性。     

宽带PLC接入技术及其最新进展

本文介绍了Homeplug电力线联盟最新颁布的HomePlug AV标准；分析了宽带PLC（电力线通信）接入网的优缺点；讨论了宽带PLC接入网的结构。PLC信道特性以及PLC使用的调制技术。随着PLC关键技术的不断成熟，PLC将有可能成为一种有效的宽带接入手段。     

宽带无线通信的核心技术OFDM

本文简述了OFDM(正交频分复用)技术的基本原理,给出了OFDM系统的构成及功能模块,论述了OFDM技术的主要特点,介绍了OFDM技术在宽带无线通信领域中的应用.     

宽带卫星通信系统中的OFDM同步技术及应用

本文介绍了宽带卫星通信,对OFDM系统的原理进行了分析,通过仿真分析等方法,重点阐述了有关宽带卫星通信系统中的OFDM同步技术应用效果方面的问题,证实了技术应用的有效性.     

高校宽带组网方案研究

宽带是高校学生的刚性通信需求,高校宽带组网具有区别于普通家庭宽带的特点以及特殊的管理要求.本文阐述了主流有线接入技术应用于高校宽带组网的多种方案,分析比较了不同方案的造价和技术优劣,提出了高校宽带组网优选技术方案.     

移动通信系统中OFDM技术的分析及其应用

OFDM是一种多载波数字调制技术,是未来无线宽带接入系统的基本实现技术之一及下一代蜂窝移动网络的无线接入技术。     

宽带无线通信的核心技术OFDM

本文简述了OFDM（正交频分复用）技术的基本原理，给出了OFDM系统的构成及功能模块，论述了OFDM技术的主要特点，介绍了OFDM技术在宽带无线通信领域中的应用。     

OFDM在无线通信中的应用研究

阐述了宽带无线通信技术中OFDM的发展现状及其在无线通信中的优势。同时就OFDM系统中的关键技术进行了具体分析和研究。     

浅谈宽带电力线载波通信系统的发展及应用

宽带电力线载波通信系统把将原有的电力线网络改装成电力线通信网络,不需要重新布线,使用方便快捷。本文简单介绍了宽带电力线通信的发展历程、应用现状、采用的技术等,可以看到该项技术有广阔的发展前景。     

基于OFDM的无线接入技术

本文首先介绍了正交频分复用技术(OFDM)的原理、技术优点,它在无线局域网中的应用特点.然后分析了在宽带无线接入技术中,三种基于OFDM而发展起来的技术,VOFDM、WOFDM和flash-OFDM的性能特点,最后展望了OFDM在未来移动通信系统中的应用.     

CIGS薄膜(InGa)2Se3-富Cu-富In(Ga)的演变

采用三步共蒸发工艺顺序沉积铜铟镓硒(CuInGaSe2,CIGS)薄膜.薄膜的厚度、组份、晶相结构分别由台阶仪、X射线荧光光谱仪(XRF)和X射线衍射仪(XRD)来表征.在(In,Ga)2Se3预制层-富Cu相的演变过程中,依次发生以下相变:Cu(In,Ga)5Se8、Cu(In,Ga)3Se5、Cu2(In,Ga)4Se7(或Cu(In,Ga)2Se3.5)、Cu(In,Ga)Se2(液相CuxSe).在富Cu相-富In(Ga)相的演变过程中,依次发生以下相变:Cu(In,Ga)Se2(液相CuxSe)、Cu2(In,Ga)4Se7(或Cu(In,Ga)2Se3.5)、Cu(In,Ga)3Se5、Cu(In,Ga)5Se8.对这两个演变过程中薄膜的生长机理和结构特性进行了讨论.     

Boron retarded diffusion in the presence of indium or germanium

Experimental results of germanium (Ge) and indium (In) preamorphization by ion-implantation show that the diffusion of boron (B) is retarded by the presence of Ge or In and that this retardation is more important than the preamorphization (dechanneling) effect. Result shows that In retards B diffusion more than Ge and the retardation effect due to In becomes greater with increasing retained dose of In. Larger In doses cause larger strain, which results in more B being tied up in immobile clusters near the surface. In order to achieve adequate retained dose of In, the implanted dose of In must be increased to 5/spl times/10/sup 15/ cm/sup -2/. After anneal, the junction depth (at 10/sup 18/ cm/sup -3/) is reduced from 628 /spl Aring/ in the control wafer (no In co-implant) to 480 /spl Aring/.     

Outage analysis of TAS/MRC in dual hop full-duplex MIMO relay networks with co-channel interferences

In this paper, we investigate the outage performance of transmit antenna selection (TAS) and maximal-ratio combining (MRC) in dual hop full-duplex (FD) amplify-and-forward (AF) relay network over Rayleigh fading channels. In the analysis, Rayleigh faded multiple co-channel interferers (CCIs) are also taken into account at the relay. In the network, source and destination are equipped with multiple antennas, and relay is equipped with one receive and one transmit antennas, respectively and source-destination link is not available. While the TAS is applied at the source without considering residual self-interference (RSI) effect, received signals at the destination are combined based on the MRC technique. For the analysis, we consider three approaches at the relay. In the first, we consider the received signal at the relay is corrupted by faded RSI and noise, in the second one, the RSI is considered as non-fading. In the last one, the noise is neglected. In all cases, the relay suffers from multiple Rayleigh faded CCIs. Outage probability (OP) expression related to all the cases is derived and obtained in single integral forms in case of the faded/non-fading RSI and in closed form in case of the noise neglected approach. Moreover, we also find asymptotic OPs and conduct effective diversity order analysis. The analytical results are verified by the Monte Carlo simulations. Results show that TAS decreases error floor at high signal-to-noise ratio (SNR) region and MRC provides diversity gain at low SNR region. In addition, approaches II and III are good approximations to approach I at low and high SNR regions, respectively.     

Raman Scattering in GaxIn1-xP and (AlxGa1-x)0.51In0.49P Alloys

Raman scattering spectroscopy is applied to investigate the phonon modes in GaxIn1-xP (x=0.52) and (AlxGa1-x)0.51In0.49P (x=0.29) alloys. Two-mode behavior in GaxIn1-xP and three-mode behavior in (AlxGa1-x)0.51In0.49P are observed. In ordered GaxIn1-xP, we clearly distinguish the TO1(GaP-like) mode and the splitting of LO1(GaP-like) and LO2 (InP-like) modes, which is believed to be the result of superlattice effect of ordering, and the LO1 LO2 mode, which is observed for the first time. In addition to the b/a ratio, it‘s found that the relative intensity of the FLA and the LO1 LO2 modes also corresponds to the degree of order. The TO1 and the splitting of LO1 and LO2 devote together to the reduction of the “valley depth“. In (AlxGa1-x)0.51In0.49P, the doubling of FLA is observed. Due to the influence of Al composition, the GaP-like LO mode becomes a shoulder of the InP-like LO mode. The unresolved Raman spectra indicate the existence of ordered structure in (AlxGa1-x)0.51In0.49P alloys.     

一种汉语语音变换技术

汉语语音变换技术的目的是将汉语语音中源说话人的语音特征转换为目标说话人语音特征。提出的适用于汉语说话人的变换算法分为3个部分:前两部分用高斯混合模型实现了语音的谱包络(线性预测编码)及其激励(残差)的转换;第三部分采用支持向量回归算法实现语音的韵律变换规则建模,结合汉语语音特点利用基音同步叠加算法实现语音的超音段特征调整。与现有的语音变换算法进行比较,算法针对汉语语音超音段发音特点进行韵律调整,有效实现了汉语语音变换并得到高自然度合成语音,是一种有效的汉语语音变换算法。     

CdO对In2O3电导和气敏性能的影响

为探索新型CdO-In2O3材料的气敏性能,用化学共沉淀法制备了CdO掺杂的In2O3微粉,研究了CdO掺杂对In2O3电导和气敏效应的影响。结果表明CdO和In2O3间能形成有限固溶体In2-CdxO3(0≤x≤0.02);In1.98Cd0.02O3x的电导比纯In2O3小得多;900℃下热处理4h所得的x(CdO)为2%的In2O3传感器在183℃工作温度下,对45μmol·L–1C2H5OH的灵敏度达276、响应–恢复时间只有3s和180s。有望开发为一类新型酒敏材料。     

一种快速多模态图像匹配导航方案

为了能在飞行器自主导航系统中快速,精确地完成不同模态图像间的匹配,该文提出了一种基于多分辨率分析的图像匹配导航方案。这种方案采用金字塔结构,由粗到细进行匹配。在最小尺度上,采用了逐步剔除的策略,提出了边缘膨胀模板(EDT),并推导了快速算法;在中间级别上,用Hausdorff distance作为相似准则;在最后一级别上,采用交互方差进行匹配。在匹配过程中,除最小尺度上采用快速算法外,在其他匹配阶段也推导和采用了一些加速算法来减少运算量。实验结果显示该文的方法可以快速,精确地完成多模态图像匹配。另外,该文方法易于硬件实现,有助于图像匹配导航系统的工程实现。     

基于正交频分复用的频域差分幅度相位调制

该文提出一种基于频域的幅度两电平的DAPSK+OFDM,并讨论该调制方式在频域的差分调制和解调,然后给出它在白高斯信道的误比特性能公式。最后在典型的调幅(AM)波段信道对它和基于时域的DAPSK+OFDM的误比特性能进行了仿真。结果表明:在短波信道,频域的DAPSK+OFDM比时域的DAPSK+OFDM性能好;在中波信道,时域的DAPSK+OFDM比频域的DAPSK+OFDM性能好。因此,数字调幅广播系统在短波信道可采用频域DAPSK+OFDM,在中长波信道可采用时域DAPSK+OFDM     

SOP集成技术的发展现状及其在毫米波系统中的应用

介绍了SOP(System On Package)集成技术,并与传统系统集成方法以及SOC(System On Chip)、MIP(Module In Package)、MCM(Mult i Chip Module)、SIP(System In Package)等微封装、微集成技术进行了比较和分析,揭示了SOP小型化、低成本、高可靠性、高性能特点。对SOP在毫米波系统应用、新材料和新工艺的进展进行了总结,结果表明SOP在毫米波系统中具有良好的应用前景。     

Precise and efficient Chinese license plate recognition in the real monitoring scene of intelligent transportation system

In this paper, the performance of you only look once ( YOLO) series detectors on Chinese license platerecognition (LPR) in the real intelligent transportation system (ITS) monitoring scene is investigated. Specially, aprecise and efficient automatic license plate recognition ( ALPR ) system based on the YOLOv4 detector isproposed. The proposed ALPR system contains three stages including vehicle detection, license plate detection(LPD) and LPR. In vehicle detection stage, YOLOv4 detector is directly applied. In LPD stage, YOLOv4-tinydetector is exploited. In the last stage, the YOLOv4-tiny detector with attention mechanism for LPR is proposed touse. In addition, a large Chinese license plate dataset containing 10 500 images collected from all 31 provinces inthe Chinese mainland is created. This Chinese license plate dataset is named Hefei University of Technology licenseplate version 1 (HFUT-LP v1). Particularly, HFUT-LP v1 dataset is collected in the real ITS monitoring scene. Inorder to compare the performance of different object detection algorithms for ALPR, a variety of object detectionalgorithms are used to make a comprehensive performance evaluation. Experimental results show that theproposedALPR system achieves very high accuracy and has very fast processing speed, which is suitable for real-time LPR.