基于时间差和角度的数据融合定位算法研究

定位系统中大部分现在存在的算法通常没有考虑综合利用空域、时域信息,而只选择了少量的测量信息.为了克服这个缺陷,提出了一种新的TDOA/AOA数据融合定位算法,这种算法充分利用了来自多个传感器的冗长信息,其中包括到达时间、到达方向.仿真实验结果表明与传统的算法相比,这种算法具有更好的定位精度和收敛速度,进一步改进了系统的可靠性,是一种有效、可行的定位算法.     

A source authentication scheme based on message recovery digital signature for multicast

The source authentication is an important issue for the multicast applications because it can let the receiver know whether the multicast message is sent from a legal source or not. However, the previously related schemes did not provide the confidentiality for data packets. In addition, the communication costs of these schemes are still high for real‐time applications in the multicast environments. To solve the aforementioned problems, we propose a new source authentication scheme based on message recovery signature for multicast in this paper. In the proposed scheme, the encrypted data can be embedded in the digital signature, so the communication loads can be greatly reduced. In addition, the digital signature contains the encrypted data, and thus the confidentiality of data packets can be well protected. According to the aforementioned advantages, the proposed scheme is securer and more efficient than the related works for the real‐time applications. Copyright © 2013 John Wiley & Sons, Ltd.     

适用于纹波控制型DC-DC控制器的比较器设计

设计一种适用于纹波控制（Output-Ripple-Based Control）的Buck型DC-DC控制器的比较器,根据PSIM搭建的仿真模型,分析主环比较器性能对系统的影响,设计具有三级预放大的高增益,低延时,低失调电压的比较器电路,采用两种温度系数的电流补偿比较器增益,稳定增益,采用0.5umBiCOMS工艺进行仿真验证,下降沿延时27ns,增益123dB,随温度最大增益变化3.2%,失调电压90uV,达到系统要求。     

Design,fabrication and characterization of miniature RF MEMS switched capacitor based phase shifter

This paper aims to present in detail the design, fabrication and the various characterization techniques adopted in realizing a novel miniature-size switched capacitor based phase shifter. The work strives to provide an all-round development of a DMTL (Distributed MEMS Transmission Line) based phase shifting unit yielding an overall phase shift of 15° at a frequency of 15 GHz. The RF MEMS (Radio Frequency Micro Electro Mechanical Systems) Switched Capacitor based phase shifter has highly miniaturized dimensions, and is capable of solving many limitations to which the conventional Switched Capacitors are mostly susceptible. This miniature RF MEMS switched capacitor actuates at a low actuation voltage of 12 V, exhibits a fundamental frequency of vibration as high as 1.468 MHz and a switching time of 1.4 µs which is an improvement over the other reported designs. Various characterization results seem to validate the simulations.     

局域寿命控制NPT-IGBT瞬态模型

提出了局域寿命控制下NPT-IGBT的瞬态模型,并与数值分析结果进行了对比,验证了模型的正确性.该模型采用了准静态近似,将关断过程分为快速下降阶段和缓慢下降阶段分别加以求解而得到.基于该模型,详细讨论了局域低寿命区参数对关断时间的影响.该模型将有助于理解局域寿命控制NPT-IGBT的关断过程物理图像,同时也可以用于指导该类器件的设计和优化.文中所采用的分析方法具有一定的普适性,其他类似结构和器件亦可采用此方法进行分析.     

基于ForCES协议的软件集群路由器模型研究

文章提出了软件集群路由器的参考模型。且对软件集群路由器模型的物理结构、逻辑结构和流量场景进行了深入的分析。通过一个简单的模型实例，提出了总体设计的方案。     

空中移动目标位置测量系统设计

GPS定位技术的出现和不断发展完善,为空中移动目标的实时定位提供了新的技术途径。针对技术指标和应用环境要求,利用差分GPS定位和无线数据传输相结合的方式,实现空中移动目标的位置测量。空中目标采用嵌入式系统实现位置数据的采集、存储与发送;地面移动站利用无线传输链路接收空中目标的位置,并实时显示空中目标相对于自身的空间坐标。实际测试结果表明,相对定位精度在1 m以内,验证了系统设计,为空中移动目标的实时位置测量提供了技术手段。     

雷达动目标极化散射矩阵瞬时测量技术

研究了雷达运动目标的信息获取问题,提出了运动目标极化散射矩阵瞬时测量方法。雷达正交双极化天线同时发射正、负调频斜率线性调频信号,目标的正交双极化回波分别与2个线性调频信号进行匹配滤波,利用正、负斜率线性调频信号的模糊函数特性测量目标时延和多普勒频移,通过求解线性方程组消除极化-多普勒耦合,精确得到目标极化散射矩阵的4个元素。该方法可以在单个脉冲周期内同时获取目标的距离信息、速度信息和极化信息。仿真实验验证了该方法的有效性。     

一个简单鉴频鉴相器结构实现的快速锁定低抖动锁相环

用简单的鉴频鉴相器结构实现了一个快锁定低抖动的锁相环.鉴频鉴相器仅仅由两个异或门组成,它可以同时获得低抖动和快锁定的性能.锁相环中的电压控制振荡器由四级环形振荡器来实现,每级单元电路工作在相同的频率,并提供45°的相移.芯片用0.18μm CMOS工艺来实现.PLL输出的中心频率为5GHz,在偏离中心频率500kHz处,测量的相位噪声为-102.6dBc/Hz.锁相环的捕获范围为280MHz,RMS抖动为2.06ps.电源电压为1.8V时,功耗仅为21.6mW(不包括输出缓冲).     

Demonstration of a 4-Sensor Folded Sangac Sensor Array with Active Phase Biasing Scheme

A 4-sensor folded Sagnac sensor array with an active phase biasing scheme is presented. The overlapping of the signal and noise pulse is avoided through a time division multiplexing scheme and the noise pulses is eliminated almost completely. The scheme can address 16 sensors when the repeat frequency of input pulse is at 68.3 kHz. The alternative phase bias technique is demonstrated, which can provide sensors with stable phase bias. The future benefit of this technique is that the 1/f noise in the circuit can be suppressed.