介质覆盖无限长导电圆柱上缝隙辐射的GTD解

本文得到了薄介质覆盖无限长导电圆柱上缝隙辐射的高频渐近结果,它以GTD的简洁形式表示,并在过渡区连续。本文利用GTD解,计算了归一化方向图,讨论了介质层厚度及介电系数ε_r的影响。本文解与精确解吻合好,计算速度迅速。     

利用带限信号的部分时域和频域信息恢复离散信号

本文提出了离散情况下利用带限信号的部分时域信息和部分频域信息而不知道频带进行信号恢复的问题,分析了进行信号重构时解的可能性,给出了最小二乘解法,并且在有多个解的情况下,给出了最小能量准则,以此为基础确定了最小能量解,并且给出了最小能量解的解析形式.仿真结果表明本文提出的方法是行之有效的。     

相关器的正弦稳态分析

本文用正弦稳态分析的方法给出了相关器的数学解,并用此稳态数学解分析了相关器的性能。     

一种基于加权迭代贪婪算法的InSAR相位解缠的新方法

该文针对干涉SAR二维相位解缠问题,提出了一种利用贪婪算法提高解缠精度的新方法.首先从理论上推导了贪婪算法相位解缠的基本原理,然后提出了一种迭代加权的贪婪算法,以克服传统贪婪算法解缠结果收敛于局部最优解的弊病,最后利用仿真数据和实际数据进行实验分析,验证了本文算法的有效性.     

北斗短基线高精度相对定位软件实现及结果分析

本文首先介绍了北斗短基线高精度相对定位软件的算法实现和工作流程,对静态基线解算和RTK解算的异同进行了总结,对短基线的静态解算精度、时段长度和RTK解算精度进行了测试和分析。实测结果表明:静态基线解算各时段解算精度平面优于1cm+1ppm,高程优于1cm+2ppm,短基线适宜的解算时段长度为1小时至1.5小时;RTK解算精度低于静态基线解算精度,在1sigma情况下,RTK解算的平面精度和高程精度接近静态基线解算精度水平。     

卡尔曼跟踪滤波器的解析稳态解

本文给出了用于边扫描边跟踪雷达系统的卡尔曼跟踪滤波器稳态解的解析表达式。雷达探测装置测量距离和临近速度,这两个测量结果要用在跟踪滤波器中,而按照特例只能获得距离测量结果的解。同时,本文还绘出了曲线图,图上示出了稳态解与不同参数的关系。     

一种新的GPS快速整周模糊度解算算法

本文实现了一种新的GPS快速整周模糊度解算算法,首先采用Kalman滤波估计初始浮点模糊值,然后采用FASF（快速模糊度搜索滤波器）和Z变换联合的方法解算整周模糊度,并给出了计算机实验结果。相对于传统的模糊度解算算法,本文采用的整周模糊度解算方法具有效率更高、更便于实时和动态应用的特点,本文的研究可作为GPS实时高动态定位和GPS实时姿态测量的工程应用的参考。     

一种新型的抗突发误码编码技术

本文介绍了交织、解交织技术的原理,及在卫星通信中用单片机实现交织、解交织技术的方法。     

最大匹配问题的DNA表面计算模型

本文给出了一个最大匹配问题的DNA表面计算模型,我们在表面上逐步生成解空间的同时,利用酶切技术删除所产生的"不可行解",从而大大减少了最终生成的解空间.最后,我们还研究了边的排列顺序对解空间的生成过程的影响.结果表明,通过对图中的边进行合理的编排也能减小不可行解的生成.     

非线性介质平板中的光波导模

本文研究了三层克尔型非线性介质平板波导中ＴＥ波的传输特性，本问题迄今只有数值解，本文则给出了严格的解析解。     

An X‐Band Carbon‐Doped InGaP/GaAs Heterojunction Bipolar Transistor MMIC Oscillator

This paper addresses a fully‐integrated low phase noise X‐band oscillator fabricated using a carbon‐doped InGaP heterojunction bipolar transistor (HBT) GaAs process with a cutoff frequency of 53.2 GHz and maximum oscillation frequency of 70 GHz. The oscillator circuit consists of a negative resistance generating circuit with a base inductor, a resonating emitter circuit with a microstrip line, and a buffering resistive collector circuit with a tuning diode. The oscillator exhibits 4.33 dBm output power and achieves ?127.8 dBc/Hz phase noise at 100 kHz away from a 10.39 GHz oscillating frequency, which benchmarks the lowest reported phase noise achieved for a monolithic X‐band oscillator. The oscillator draws a 36 mA current from a 6.19 V supply with 47.1 MHz of frequency tuning range using a 4 V change. It occupies a 0.8 mm × 0.8 mm die area.     

Identification of the source of an interferer by comparison with known carriers using a single satellite

We describe a method for identifying the source of a satellite interferer using a single satellite. The technique relies on the fact that the strength of a carrier signal measured at the downlink station varies with time due to a number of factors, and we use a quantum‐inspired algorithm to compute a “signature” for a signal, which captures part of the pattern of variation that is a characteristic of the uplink antenna. We define a distance measure to numerically quantify the degree of similarity between two signatures, and by computing the distances between the signature for an interfering carrier and the signatures of the known carriers being relayed by the same satellite at the same time, we can identify the antenna that the interferer originated from, if a known carrier is being relayed from it. As a proof of concept, we evaluate the performance of the technique using a simple statistical model applied to measured carrier data.     

A quad-rotor system for driving and flying missions by tilting mechanism of rotors: From design to control

This article presents the hybrid design and control of a quad-rotor system called Flymobile. Flymobile is a combined system of a mobile robot and a quad-rotor system aimed to perform both flying and driving tasks. Flymobile performs flying tasks in the same way as conventional quad-rotor systems while the tilting mechanism of each rotor allows Flymobile to navigate in its terrain for a driving task. The body frame with rotors is implemented by a calibration process through a test-bed equipped with a force sensor. The triangular wheel frame is designed to mimic motions of a mobile robot with three passive wheels. Sensor data of a gyro and an accelerometer are filtered and used for controlling the attitude of the system. Focusing on a practical approach of implementing a hybrid system, a non model-based approach is applied to control Flymobile. Experimental studies are demonstrated to show the feasibility of performing both driving and flying missions.     

DSP在捷联惯性制导技术中的应用

捷联惯性制导系统由于没有稳定的平台而需要通过大量的数学运算建立数学平台 ,因此制导对计算装置的性能要求很高。DSP芯片的出现为这种需要大量实时计算的制导系统提供了方便的应用方案。文中介绍了一种用DSP芯片设计的捷联惯性制导系统 ,给出了整个系统的电路和程序设计方法     

Ku波段上变频组件的设计

介绍了Ku波段上变频组件的设计与制作,整个组件由低相噪振荡器、滤波器、功分器、功率放大器、PIN开关、上变频器等部分组成。文章分别对一些主要部件进行了简要的理论分析,并给出微波电路的结构形式,最后给出样品的测试结果。     

Performance analysis by simulation of floating-gate MOSFETs applied on a bidirectional associative memory architecture

Floating-gate MOSFETs (FGMOSFETs) are devices that can be electrically programmable and have a non-volatile characteristic. This feature can be adopted to configure a basic cell performing as a variable resistance that can be applied in artificial neural networks as a synapse. Based on a simple model and considering the coupling coefficient of the structure as the gain of a voltage controlled voltage source, the electrical characteristics of a floating-gate MOSFET can be simulated in PSpice and an artificial neural net, such as the bidirectional associative memory (BAM), can be implemented. Therefore a performance analysis of the net may be done with different sets of threshold voltages for the FGMOSFETs configured as a CMOS inverter used as a synapse. The objective is to know pattern pairs in a bidirectional way. The result is a correlation matrix for the BAM as a function of an electrical parameter of the devices, which is directly related to the respective matrix calculated by the matrix dot product, using the method outlined by Kosko.     

Longitudinally Excited CO<Subscript>2</Subscript> Laser with Short Laser Pulse like TEA CO<Subscript>2</Subscript> Laser

We have developed a longitudinally excited CO₂ laser with a short laser pulse similar to that of TEA and Q-switched CO₂ lasers. A capacitor transfer circuit with a low shunt resistance provided rapid discharge and a sharp spike pulse with a short pulse tail. Specifically, a circuit with a resistance of 10 M Ω provided a spike pulse width of 103.3 ns and a pulse tail length of 61.9 μs, whereas a circuit with a shunt resistance of 100 Ω provided a laser pulse with a spike pulse width of 96.3 ns and a pulse tail length of 17.2 μs. The laser pulses from this longitudinally excited CO₂ laser were used for processing a human tooth without carbonization and for glass marking without cracks.      

Optical and electrical characteristics of GaN vertical light emitting diode with current block layer

A GaN vertical light emitting diode(LED)with a current block layer(CBL)was investigated.Vertical LEDs without a CBL,with a non-ohmic contact CBL and with a silicon dioxide CBL were fabricated.Optical and electrical tests were carried out.The results show that the light output power of vertical LEDs with a non-ohmic contact CBL and with a silicon dioxide CBL are 40.6%and 60.7%higher than that of vertical LEDs without a CBL at 350 mA,respectively.The efficiencies of vertical LEDs without a CBL,with a non-ohmic contact CBL and with a silicon dioxide CBL drop to 72%,78%and 85.5%of their maximum efficiency at 350 mA,respectively. Moreover,vertical LEDs with a non-ohmic contact CBL have relatively superior anti-electrostatic ability.     

A 0.13 μm CMOS UWB RF Transmitter with an On‐Chip T/R Switch

This paper presents a fully integrated 0.13 μm CMOS MB‐OFDM UWB transmitter chain (mode 1). The proposed transmitter consists of a low‐pass filter, a variable gain amplifier, a voltage‐to‐current converter, an I/Q up‐mixer, a differential‐to‐single‐ended converter, a driver amplifier, and a transmit/receive (T/R) switch. The proposed T/R switch shows an insertion loss of less than 1.5 dB and a Tx/Rx port isolation of more than 27 dB over a 3 GHz to 5 GHz frequency range. All RF/analog circuits have been designed to achieve high linearity and wide bandwidth. The proposed transmitter is implemented using IBM 0.13 μm CMOS technology. The fabricated transmitter shows a ?3 dB bandwidth of 550 MHz at each sub‐band center frequency with gain flatness less than 1.5 dB. It also shows a power gain of 0.5 dB, a maximum output power level of 0 dBm, and output IP3 of +9.3 dBm. It consumes a total of 54 mA from a 1.5 V supply.     

Virtual impedance control for a regional dynamic voltage restorer

A dynamic voltage restorer (DVR) can be installed in a middle-voltage (MV) power grid, to concurrently protect a cluster of sensitive loads from voltage sags. To further improve its efficiency and reduce the difficulty in its implementation, a novel control strategy for operating such a DVR as a virtual impedance in series with sensitive loads is proposed in this paper. In addition to its usual function of compensating for voltage sags, such a DVR can also operate as a virtual inductance, to function as a fault current limiter (FCL) during a downstream fault, or a virtual capacitance, to function as a series compensator (SC) to compensate the voltage loss along the feeder line during heavy load. Based on a dual-loop control design, strategies for operating a DVR as a series virtual inductance and a virtual capacitance are proposed, and methods for tuning the parameter values and a stability analysis of the whole system are presented. The feasibility and effectiveness of the proposed method are verified by simulations using the PSCAD software, and experimental results obtained using a prototype DVR are presented.