播出系统中KII与PVS两代硬盘服务器的混合使用

目前Profile硬盘服务器的用户存在的现实问题是,在对系统进行升级改造时,在PDF和PVS系列硬盘服务器已经停产情况下,如何使KII系列与PDF或PVS系列安全高效地混合使用,温州市广播电视总台在这方面成功地解决了这个问题,通过近一年的使用,达到了预期的效果。简述KII与PVS在播出系统中的混用,希望能给Profile用户提供一些有益经验。     

Performance of Multiband Complex-Wavelet-Based MC-CDMA System with Space-Time Coding over Nakagami-m Fading Channels

Space-time coding technique and Multi-carrier CDMA (MC-CDMA) technique have received much interest due to their high frequency spectrum efficiency and high data rate transmission. On the basis of analyzing the two technique principle, utilizing the optimized multiband complex wavelet as multi-carrier basis function, we propose an MC-CDMA system based on multiband complex wavelet and space-time coding for downlink and investigate the system bit error rate (BER) performance over Nakagami-m fading channel. The system has much higher spectrum efficiency and data rate due to no need any cyclic prefix (CP) when compared to the conventional MC-CDMA system. Moreover, the application of space-time coding technique improves the ability against fading channel effectively and perfects the downlink performance further. Simulation results show that the proposed multiband complex-wavelet-based MC-CDMA (MBCW-MC-CDMA) system performs better than conventional MC-CDMA system and real wavelet-packet-based MC-CDMA system due to its superior ability against interferences. Especially, the space-time coded MBCW-MC-CDMA system has superior performance, and it outperforms single antenna MBCW-MC-CDMA and conventional MC-CDMA with space-time coding.     

遥测脉码调制（PCM）编码的逻辑电路实现

介绍了一种采用逻辑电路实现的脉冲编码调制遥测控制电路,它满足一些特殊遥测系统的要求,并以可编程逻辑器件来实现,使系统具有较小的电路板占用面积。该方案可以用于需要以脉冲编码调制方式传输信号的便携式测量系统。     

一种基于频域的视频压缩算法及其实现

提出了一种基于频域的视频编码的方案并描述其如何实现，该算法利用DCT变换和运动图像前后帧在频域的三种状态，对图像快速高效编解码，运算量低，可在PC机上用软件实时实现。     

基于EDGE系统信道估计实现方案的研究

研究了基于ＥＤＧＥ系统接收机中信道估计的实现方案，并对算法的各项性能做出评估。首先论述了算法的采用及其理论依据。接着，说明了信道预估计的原理及方法。最后，针对ＭＡＴ－ＬＡＢ及 ＤＳＰ上的仿真结果，比较了各项系数对于系统性能改善所具有的影响和作用，对系统特性作了较为详细的分析总结。     

P N IFFT FOR OFDM-BASED UWB SYSTEM

In this letter, P × N-point IFFT is proposed to replace the N-point IFFT and analog frequency conversion in an Orthogonal Frequency Division Multiplexing (OFDM)-based Ultra-WideBand (UWB) system, and a new algorithm, named fast P × N-point IFFT, is designed to reduce the complexity of the P × N-point IFFT in the proposed scheme.     

宽带无线接入技术的发展现状与趋势

阐述了宽带无线接入技术的发展现状以及未来发展趋势,主要分析了其中的WiMAX、UMTS、TDD、FLASH-OFDM技术.     

Trusted Next Generation Internet and Its Development

The ongoing research on secure and trustworthy issues in next generation Internet technology is still insufficient. China has achieved some progress in the field of the trusted next generation Internet. Under the support of the National High Technology Research and Development Program of China (863 Program), Tsinghua University and other units have completed the program named "Research on Critical Technologies and Demonstration Applications of the Trusted Next Generation Internet", which targets the secure and trustworthy problems existing in the current Internet. With focus on tackling the technical problem of authentic address access in the Internet, a prototype system for trusted Internet infrastructure, security service and typical applications are designed and implemented. It is expected that the trusted next generation Internet will support the trusted computer network, trusted telecom network and trusted broadcast & TV network applications.     

Ultra-Wideband Electrostrictive Mechanical Antenna

Mechanical antennas based on piezoelectric materials can effectively reduce the size of long wave antennas down to 1/1000 of the wavelength (from km scale to mm level). However, the narrow bandwidth and weak field intensity seriously restrict its practical applications in transmission distance and channel capacity. Here, a mechanical antenna-based electrostrictive effect of relaxor ferroelectric ceramic (PMN-PT) is proposed to improve radiation capacity and achieve ultra-wideband characteristics (10 kHz–1 MHz). Due to the ultra-high dielectric constant at working temperature and the relationship between the strain and applied field intensity, the proposed antenna gets rid of the dependence on the poled materials and exhibits excellent communication properties beyond traditional mechanical antennas, which are experimentally demonstrated by a practical wireless communication system. Only using a single proposed mechanical antenna with 8 mm diameter and 3 mm thickness, the effective communication with a transmission distance of 200 m can be realized. This design offers a promising way of constructing mechanical antennas for long-wave communication.     

Boosting Piezo-Catalytic Activity of KNN-Based Materials with Phase Boundary and Defect Engineering

Although the piezo-catalysis is promising for the environmental remediation and biomedicine, the piezo-catalytic properties of various piezoelectric materials are limited by low carrier concentrations and mobility, and rapid electron-hole pair recombination, and reported regulating strategies are quite complex and difficult. Herein, a new and simple strategy, integrating phase boundary engineering and defect engineering, to boost the piezo-catalytic activity of potassium sodium niobate ((K, Na)NbO₃, KNN) based materials is innovatively proposed. Tur strategy is validated by exampling 0.96(K_0.48Na_0.52)Nb_0.955Sb_0.045O₃-0.04(Bi_xNa_4-3x)_0.5ZrO₃-0.3%Fe₂O₃ material having phase boundary engineering and conducted the defect engineering via the high-energy sand-grinding. A high reaction rate constant k of 92.49 × 10⁻³ min⁻¹ in the sand-grinding sample is obtained, which is 2.40 times than that of non-sand-grinding one and superior to those of other representative lead-free perovskite piezoelectric materials. Meanwhile, the sand-grinding sample has remarkable bactericidal properties against Escherichia coli and Staphylococcus aureus. Superior piezo-catalytic activities originate from the enhanced electron-hole pair separation and the increased carrier concentration. This study provides a novel method for improving the piezo-catalytic activities of lead-free piezoelectric materials and holds great promise for harnessing natural energy and disease treatment.