Design of reliable universal QCA logic in the presence of cell deposition defect

The emergence of Quantum-dot Cellular Automata (QCA) has resulted in being identified as a promising alternative to the currently prevailing techniques of very large scale integration. QCA can provide low-power nanocircuit with high device density. Keeping aside the profound acceptance of QCA, the challenge that it is facing can be quoted as susceptibility to high error rate. The work produced in this article aims towards the design of a reliable universal logic gate (r-ULG) in QCA (r-ULG along with the single clock zone and r-ULG-II along with multiple clock zones). The design would include hybrid orientation of cells that would realise majority and minority, functions and high fault tolerance simultaneously. The characterisation of the defective behaviour of r-ULGs under different kinds of cell deposition defects is investigated. The outcomes of the investigation provide an indication that the proposed r-ULG provides a fault tolerance of 75% under single clock zone and a fault tolerance of 100% under dual clock zones. The high functional aspects of r-ULGs in the implementation of different logic functions successfully under cell deposition defects are affirmed by the experimental results. The high-level logic around the multiplexer is synthesised, which helps to extend the design capability to the higher-level circuit synthesis.     

Adaptive Resource Sharing Strategies for UMTS Multiservice Mobiles

In this paper, a multiservice transmission scheme which joints voice, video, interactive game and signaling is evaluated for the dedicated channel of the Universal Mobile Telecommunications System. The transmission rate for each service is determined by means of an adaptive transport format selection. In the UMTS standard, this selection is based on power allocation provided by radio resource controller, trying to match the Eb/No requirements of the individual services. An appropriate selection of the individual rates of each multiplexed service, taking into account its particular QoS requirements, will provide a more efficient resource management than the transmission only restricted to power allocation. For this purpose, we propose and evaluate a new selection strategy based on buffer occupation, delay requirements and target bit rate keeping power constraints that intends to improve the basic operation trying to minimize the impact of the whole network. Video and game services are multiplexed in upper layers (logical channels) sharing a common transmission rate (transport channel). In this paper, it is proposed a new strategy to share the transmission rate set for this transport channel between both services taking into account their particular requirements. Results show that considering delay constraints provides a more balanced performance of the multiplexed services.     

基于锁相放大器的万能试验机采集系统研制

基于STM32、STM8处理器,设计完成了万能试验机的多个功能模块。为了提高小信号的采集精度与速度,用多处理器设计了一种混合式的锁相放大器,并运用数字处理进行进一步处理,具有很高的性价比。在位移信号采集中,运用STM8S实现了低成本的设计。实验表明,本系统在速度与精度上满足万能试验机要求,总体性价比高。     

嵌入式USB功率控制器的设计

针对目前大多数系统级芯片对多电源供电的要求,设计了一款嵌入式通用串行总线(USB)功率控制器,并对该控制器进行了理论分析.其中主要阐述了电路内部自动进行电流采样和限流电路的工作原理及实现方法.USB功率控制器严格地将输出电流限制为500 mA/100 mA.在CSMC 0.5 μm CMOS工艺上,利用Cadence仿真平台进行验证,结果表明,在所有条件下,从USB总线吸收的电流均受到精确的限制,仿真结果符合理论分析.     

一种基于Zynq-7000+AD9361的通用调制平台设计

针对一般调制平台互联性差、灵活性差、复用性差等问题,采用软硬件协同设计和部分动态可重配置等技术,设计了一种基于Zynq-7000和AD9361的通用调制平台。采用16APSK和QPSK的调制方式对通用调制平台的设计进行验证,其中平方根升余弦成形滤波器采用查找表形式的多相滤波器结构实现,该实现方法只用到加法运算。测试结果表明,在不同Zynq-7000开发板和不同调制方式下,替换部分硬件功能模块和修改软件配置,平台均能正常工作。与传统调制平台相比,本平台的设计以及功能实现具有灵活性强、复用性高等特点,具有广阔应用前景。     

基于USB的DMA方式实现CCD高速数据采集

提出一种CCD用于通用串行总线(USB)高速数据采集系统设计的新方法。通过对USB及其DMA传输方式分析,采用无外部缓冲区的结构实现数据的高速传输．具有精度高、结构简单、方便易行等优点。详细描述了硬件、固件、驱动程序及应用程序的设计情况。实验证明,该系统可实现CCD的高速高精度数值量化及数据传输。     

基于NIOSⅡ的多串口数据通信的实现

串口传输常用于基于FPGA和DSP结构的信号处理板和外部设备之间的数据交换。以GPS RTK定位应用为基础,针对单个串口全双工传输不足以应对多种数据类型同时输入输出的情形,设计并实现了一种面向多串口不同类型数据的传输方案。该方案通过增加串口控制寄存器实现单个中断信号即可控制所有串口,采用乒乓交替读写实现数据持续高速输入。测试表明该方案可独立对各串口进行配置,可同时实现GPS定位结果、差分GPS修正数据与外界的交换以及用户控制命令的输入,并且可减少硬件调试时间,节约硬件资源。     

下一代接入网发展及政府的角色

经受了全球金融危机的冲击,各国尤其是发达国家都非常重视宽带的发展。同时,危机也重新唤起了人们对政府有效监管的重视,对国家适时进行干预的必要性有了更加明确的认识。目前来看,FTTx是未来宽带接入的重要技术选择,也是经济增长的热点。政府则会通过直接和间接资金投入以及政策和措施等各种方式,对宽带发展进行资助和扶持。     

Fluorene‐Based Asymmetric Bipolar Universal Hosts for White Organic Light Emitting Devices

Two new bipolar host molecules composed of hole‐transporting carbazole and electron‐transporting cyano ( CzFCN ) or oxadiazole ( CzFOxa )‐substituted fluorenes are synthesized and characterized. The non‐conjugated connections, via an sp³‐hybridized carbon, effectively block the electronic interactions between electron‐donating and ‐accepting moieties, giving CzFCN and CzFOxa bipolar charge transport features with balanced mobilities (10^?5 to 10^?6 cm² V^?1 s^?1). The meta–meta configuration of the fluorene‐based acceptors allows the bipolar hosts to retain relatively high triplet energies [E_T = 2.70 eV ( CzFOxa ) and 2. 86 eV ( CzFCN )], which are sufficiently high for hosting blue phosphor. Using a common device structure – ITO/PEDOT:PSS/DTAF/TCTA/host:10% dopants (from blue to red)/DPPS/LiF/Al – highly efficient electrophosphorescent devices are successfully achieved. CzFCN ‐based devices demonstrate better performance characteristics, with maximum η_ext of 15.1%, 17.9%, 17.4%, 18%, and 20% for blue (FIrpic), green [(PPy)₂Ir(acac)], yellowish‐green [m‐(Tpm)₂Ir(acac)], yellow [(Bt)₂Ir(acac)], and red [Os(bpftz)₂(PPhMe₂)₂, OS1], respectively. In addition, combining yellowish‐green m‐(Tpm)₂Ir(acac) with a blue emitter (FIrpic) and a red emitter (OS1) within a single emitting layer hosted by bipolar CzFCN , three‐color electrophosphorescent WOLEDs with high efficiencies (17.3%, 33.4 cd A^?1, 30 lm W ^?1), high color stability, and high color‐rendering index (CRI) of 89.7 can also be realized.     

空间飞行器姿态控制律设计

空间飞行器姿态系统具有非线性、强耦合、多输入多输出的特点。针对飞行器姿态模型的非线性和不确定性,提出了分散模糊变结构控制方法。利用模糊系统对不确定性函数进行逼近,将获得的模糊系统函数作为系统不确定性界函数。对模糊逼近所带来的误差以及外部干扰项,采用控制补偿方法。理论分析和仿真研究表明,提出的方法具有控制精度高,实时计算量小,便于工程实现等优点。