一种互补结型场效应管负阻器件

介绍了一种利用集成互补结型场效应管的简单复合而构成的负阻器件，并且对该负阻器件的温度特性进行了分析，为设计具有温度稳定性的负阻器件提供了有益的参考。     

OFDM技术在无线接入中的应用

文章首先介绍了OFDM的关键实现技术，然后结合不同无线通信环境的特点，对OFDM在无线局域网和固定无线接入中的应用进行了分析。     

SiGe MOS器件SiO_2栅介质低温制备技术研究

为了获得电学性能良好的 Si Ge PMOS Si O2 栅介质薄膜 ,采用等离子体增强化学汽相淀积 (PECVD)工艺 ,对低温 30 0°C下薄膜制备技术进行了研究。实验表明 ,采用适当高温、短时间对PECVD薄膜退火有助于降低薄膜中正电荷密度和界面态密度。该技术用于 Si Ge PMOS研制 ,在30 0 K常温和 77K低温下 ,其跨导分别达到 45m S/mm和 92 .5m S/mm(W/L=2 0 μm/2 μm)     

A 2.4GHz Low Power ASK Transmitter for Wireless Capsule Endoscope Applications

提出了一种应用于无线内窥镜系统的2.4GHz低功耗ASK发射机.为了获得高的数据传输速率,采用了基于混频器的直接上变换发射机结构.为了节省功耗,提出了一种基于电流复用技术的伪差分堆栈结构的A类功放.低功耗发射机由两部分组成:基于恒幅度锁相环(PLL)的20MHz的ASK基带调制器和直接上变换的射频电路.该设计已经采用TSMC 0.25μm CMOS工艺实现并进行了验证.测试结果表明,发射数据速率为1Mbps时,发射机的输出功率为-23.217dBm.采用单2.5V的电源供电下,低功耗发射机消耗的电流约为3.17mA.     

Implementation Issues in Turbo Decoding for 3GPP FDD Receiver

In the Frequency Division Duplex (FDD) mode of the Third Generation Partnership Project (3GPP) standard, implementation of the turbo decoder, especially for the mobile equipments, faces design decisions related to computational complexity, power efficiency, and memory requirements. In this paper we compare different approaches of low complexity implementation of the turbo decoder, with emphasis on the issues of signal scaling and quantization, the sliding window operation for memory size reduction and the iteration stopping algorithms. The demodulated signal at the output of the RAKE receiver may have a wide dynamic range and it may require many bits of precision. In order to overcome the numerical precision problem and to prevent Log Likelihood ratio (LLR) metric overflow, a scaling algorithm must be used. Our simulation results indicate that the Average Absolute (AA) algorithm using dynamic scaling outperforms other scaling schemes and it is less sensitive to the channel conditions. One of the major challenges in the implementation of a practical turbo decoder is optimization of memory requirements. In this paper we evaluate the performance of the sliding window algorithm using different main and guard window sizes. We show that the bit and block error rate performance of the sliding window scheme mainly depend on the guard window size rather than the main window size. The simulation results indicate that small guard window sizes can significantly decrease the iteration gain for large frames in fast fading channels. Iteration stopping algorithms reduce the power consumption and the latency of the decoder and help to dedicate more resources to other functions of the receiver. The block error distribution in the fading channels makes it even more essential to use an iteration stopping rule. Our simulations conclude that a rule called the minimum absolute value appears to be a very effective, low complexity and robust algorithm. Mohamadreza Marandian Hagh was born in Tabriz, Iran on January 1974. He received the B.S. and the M.S. degrees in electrical engineering from Tehran University with honors in 1996 and 1999, respectively. He is pursuing the Ph.D. degree in electrical engineering at Northeastern University, Boston. His research interests includes information theory, channel coding and iterative techniques for wireless communication systems. His current research is focused on low complexity designs for iterative receivers using Space-Time coding in time-dispersive channels. He is also interested in Exit-Chart analysis of iterative receivers. From 1996 to 1999, he was with Sana Pro Inc. as a system engineer, developing simulation tools for OFDM, WCDMA, CDMA2000. He is currently with Airvana Inc. in Chelmsford, MA and working on 1xEVDO wireless systems. Masoud Salehi received BS degree (Summa Cum Laude) from Tehran University and MS and Ph.D. degrees from Stanford University all in Electrical Engineering. Before joining Northeastern, he was with the Departments of Electrical and Computer Engineering, Isfahan University of Technology and Tehran University. From February 1988 to May 1989 Dr. Salehi was a visiting professor at the Information Theory Research Group, Department of Electrical Engineering, Eindhoven University of Technology, The Netherlands, where he did research in network information theory and coding for storage media.In 1989 Dr. Salehi joined Department of Electrical and Computer Engineering, Northeastern University. Professor Salehi is a member of the CDSP (Communication and Digital Signal Processing) Center. His main areas of research interest are network information theory, source-channel matching problems in single and multiple user systems, data compression, turbo coding, coding for fading channels, and digital watermarking. Professor Salehi’s research has been supported by research grants from the National Science Foundation (NSF), GTE, NUWC, CenSSIS, and Analog Devices. Professor Salehi has also done consulting to the industry including Teleco Oilfield Services and AT&T. Professor Salehi is currently a member of the Editorial Board of The International Journal of Electronics and Communications.Professor Salehi is the coauthor of the textbooks “Communication Systems Engineering”, Prentice-Hall 1994, 2002, “Contemporary Communication Systems Using MATLAB and Simulink” Thomson 1998, 2000, 2004, and “Fundamentals of Communication Systems”, Prentice-Hall 2005. Abhay Sharma received B.E. (Hons) Electrical and Electronics Engineering degree from Birla Institute of Technology and Science, Pilani, India in 1996 and M.S. Electrical Engineering degree from Ohio State University, Columbus in 2000. From 2000 to 2005 he was working with Analog Devices, RF and Wireless Systems Group, Wilmington, USA, where he was working on design and implementation of algorithms for the emerging cellular communication standards. Currently he is working with Allgo Embedded Systems, Bangalore, India, in the area of wireless networks and systems based on the emerging W-PAN wireless technologies. Zoran Zvonar received the Dipl. Ing. degree in 1986 and the M.S. degree in 1989, both from the Department of Electrical Engineering, University of Belgrade, Yugoslavia, and the Ph.D. degree in Electrical Engineering from the Northeastern University, Boston, in 1993.From 1986 to 1989 he was with the Department of Electrical Engineering, University of Belgrade, Belgrade, Yugoslavia, where he conducted research in the area of telecommunications. 1993 to 1994 he was a Post-Doctoral investigator at the Woods Hole Oceanographic Institution, Woods Hole, MA, anconducted research on multiple-access communications for underwater acoustic networks. Since 1994 he has been with the Analog Devices, Communications Division, Wilmington, USA. He is the Manager of the Systems Engineering Group focusing on the design of algorithms and architectures for wireless communications, with emphasis on integrated solutions and real-time software.He was a Guest Editor of the IEEE Transactions on Vehicular Technology, the International Journal of Wireless Information Networks and the ACM/Baltzer Wireless Networks, Associate Editor of the IEEE Communications Letters and a co-editor of the books GSM: Evolution Towards Third Generation Systems, Kluwer Academic Publishers, 1998, Wireless Multimedia Networks Technologies, Kluwer Academic Publishers, 1999 and Software Radio Technologies: Selected Reading, IEEE Press, 2001. Dr. Zvonar is currently Co-Editor of the Radio Communication Series in the IEEE Communications Magazine.     

讯宝科技的RFID技术为福田汽车加速

福田作为中国全系列商用汽车领军企业,为了能够确立竞争优势,积极打造服务体系。在无线技术被广泛利用的今天,福田为了避免库存,时效,准确率等问题,经过慎重选型,选择了美国讯宝科技公司及其合作伙伴。条形码结合无线技术不但降低了库存成本,提高了客户响应速度,而且提供了准确及时的库存信息,大大提高了福田汽车在商用车市场的竞争力。     

The research on the substitution effect between the wireless and fixed telecommunication industry

1 Introduction In recent years, the telecommunication industry has been exhibiting a fast and continuous growth especially in the wireless industry. Fixed and mobile services have commonly been regarded as two different types of businesses regulated under…     

双极双栅MOS晶体管静态特性解析模型的模拟与分析

提出了一种应用于VHF和UHF的新型功率电子器件－双极双栅MOS晶体管（BDGMOSFET）,该结构是在单栅MOSFET一侧引入双极型压控晶体管（BJMOSFET）,使之在正向工作时具有MOSFET和BJT的工作特性,通态电较小,同时,减少了寄生双极晶体管效应,改善了频率特性。文章对其静态特性的解析模型进行了详细研究,在该模型基础上运用通用电路模拟软件PSPICE的多瞬态分析法模拟了BDEMOSFET的直流特性,结果表明,在同等条件下,BDGMOSFET的电流密度比双栅MOSFET提高大约30％。     

器件结构与有机ELD发光效率和寿命

描述了有机EL器件结构设计与其效率和寿命的关系,混合型结构的有机ELD的效率和寿命要比传统异质结构器件高得多。采用阳极buffer layer(如CuPc),阴极buffer layer(如LiF)以及向HTL（空穴传输层）中的染料掺杂也会明显提高效率并增加寿命,比较了不同阴极接触模式,如Al:Li/Alq3,Al/LiF/Alq,Al/LiF:Alq3/Alq3及Al/Li:Alq3/Alq3等对器件效率及寿命影响差异,结果表明,无论哪种阴极接触模式都会提高器件的效率及寿命,而对阳级buffer layer或引入染料掺杂模式,均可以控制或调整空穴的注入,阴极buffer layer是为了增加电子注入,两者目的都是为了防止或减少在发光分子（如Alq3)中被称之为“空穴阳离子”（如[Alq3]^ )的不稳定剂的产生。     

A Real Time Transport Scheme for Wireless Multimedia Communications

In wireless communications systems, a mobile station is typically equipped with limited processing capability and buffer space for transmitting and receiving. The radio link is usually found to be noisy and its propagation delay is sometimes non-negligible as compared with the packet transmission delay. And because of the necessity of flow control and packet retransmission upon error, the delay and throughput performance cannot satisfy the need of a particular traffic type, i.e., real-time multimedia. This paper presents a scheme suitable for the above condition, called the Burst-oriented Transfer with Time-bounded Retransmission (BTTR). The present scheme uses a large transmission window for sending/receiving a burst of time-sensitive data and, within this window, another smaller observation window is repeatedly used for error status feedback via the backward channel. There is time limitation on each retransmission such that the burst of data can be received in a timely manner, however, with some degradation on the packet loss rate. An analysis is given in terms of the expectations of delay, throughput, and packet drop rate. A comparison with an error-free link protocol will also be given. The result shows that the proposed scheme can meet the delay and throughput requirement under reasonable packet drop rate.