软件无线电的直接射频采样ADC系统研究

提出了一种高速混合滤波器组ADC系统，该ADC系统能对射频模拟信号(2MHz～2000MHz)直接进行模／数转换，而且分辨率达到12比特以上。显然，用此高速混合滤波器组ADC系统可以完成软件无线电的直接射频采样．     

无人机导航抗干扰接收机射频前端设计

针对现有的工业无人机导航接收机基本不具备抗干扰性能,无人机卫星导航信号易受干扰。研究在电磁干扰环境相对恶略情况下,依然能够捕获导航信号,能正常精确定位的抗干扰导航接收机,并可应用于无人设备,已经成为无人机卫星导航定位技术发展面临的重大课题。为此设计了一款小型化导航抗干扰接收机射频前端,最后对射频电路前端进行了测试,并给出测试结果,验证系统的可行性。     

软件无线电技术

现行的面向具体用途来设计不同频段、不同制式的无线电通信电台及组网的思想已经远远不能满足现代无线电通信的实际需要,因此软件无线电系统及其技术,这种革新的通信理念与体制应运而生。文章对软件无线电技术的概念、功能和关键技术进行了介绍;并阐述了软件无线电的应用和发展前景。     

毫米波有源相控阵射频前端集成制造技术

毫米波有源相控阵射频前端工艺集成度高,立体组装、先进封装材料、TR组件热路设计和芯片技术是实现有源相控阵射频前端集成制造的关键技术.综合国内外研究发展现状,系统封装、综合集成以及多功能芯片技术是有源相控阵射频前端集成制造技术的未来发展趋势.     

智能天线在军用软件无线电中的应用研究

在军用软件无线电中引入智能天线技术,可使通信系统具备良好的自适应性和智能性,现已成为军事通信领域研究的热点之一.本文简要介绍了军用软件无线电技术与智能天线结合的通信系统的优势所在,并探讨了该通信系统的几个主要关键技术问题.     

软件无线电实现快速跳频通信

基于软件无线电的技术，给出了一种快速跳频通信的实现方案，采用DSP芯片控制DDS集成芯片AD9854实现快速跳频，本文介绍了跳频通信系统的硬件结构和软件设计。     

基于软件无线电的RFID解调方法研究

提出了一种基于软件无线电的RFID解调方法。该方法采用非相干解调技术实现了RFID调制信号的解调。与相干解调技术相比,该方法具有原理简单,在解调过程中无需恢复载波等优点。仿真结果表明,该方法对2ASK和2FSK信号达到很好的解调效果。     

一种线性检测器的软件无线电实现

介绍线性检测器的统一结构模型，基于该模型，提出了线性检测器的软件无线电接收机的实现方法和硬件组成。该方法在硬件规模、算法复杂度与误码性能之间做出平衡，方便为不同业务提供不同的通信质量。     

基于软件无线电技术的AIS数字接收机总体设计

文中主要介绍了采用软件无线电、大信号动态检测、数字信号处理、多路HDLC按位智能纠错等技术的AIS数字接收机总体构建方案,及其主要特性和设计技术,通过实时接收监测范围内船舶的静态和动态信息,达到实现船舶目标监视、跟踪和识别的目的。     

发动机前端附件驱动系统静动态性能设计计算软件

发动机前端附件驱动系统(EFEAD)静动态性能设计软件EFEAD—Kit是一个自动化的设计分析工具,用于计算和评估EFEAD系统的静动态性能。文中介绍了EFEAD的静态设计和动态设计的理论,给出了EFEAD系统的建模、关键参数的计算以及求解方法。以某款EFEAD驱动系统为例,利用EFEAD—Kit设计软件对其进行了计算分析,其计算值和实测值吻合较好,表明所建立的EFEAD系统计算模型和开发的软件EFEAD-Kit的正确性。文中所采用的计算方法、计算分析软件EFEAD—Kit,为发动机前端附件驱动系统的设计提供了一个有效的计算工具。     

Superconducting accelerometer using niobium-on-sapphire rf resonator

An accelerometer is described which uses a rf niobium-on-sapphire resonator as its sensor element. The accelerometer uses a magnetically levitated spool as a test mass and the spool modulates the inductance of the resonator; its position is servo controlled to maintain the resonator at the external rf excitation frequency. The accelerometer has high sensitivity over the full audio frequency range, but is optimized for frequencies between 100 Hz and 1 kHz, where the calculated displacement sensitivity approaches 10(-15) cm for a 1 Hz measurement bandwidth. The system noise sources are analyzed and possible improvements are discussed.     

新一代天气雷达资料整编软件的研制与开发

为便于对新一代天气雷达灾害性天气过程个例资料进行整编,利用VC编写程序,主要解决雷达基数据读取、记录时间格式转换和按规定格式进行文件更名。本文介绍软件的设计思路、软件功能和程序开发技巧。     

经济型快速成型技术的软件系统研究

提出了经济型快速成型系统的概念 ,研究开发了用于经济型快速成型技术的软件系统 ,并介绍了这一软件系统的开发过程和方法     

Electrical characterization of a capacitive rf plasma sheath

The authors report on an experimental system designed to investigate and characterize capacitive radio frequency (rf) sheaths. An electrode mounted in an inductive plasma reactor and driven with separate rf and direct current (dc) power sources is used. The advantage of this design is that the electrode sheath is decoupled from the plasma parameters. This allows detailed investigation of the sheath with different bias conditions without perturbing the bulk plasma parameters. Power coupled to ions and electrons through the sheath, at low pressure, is investigated and a method to determine the electron conduction current to the electrode, using the external dc bias, is presented.     

Fabrication and properties of rf niobium-on-sapphire superconducting resonators

Niobium-on-sapphire resonators have been constructed as sensor elements for accelerometers in gravitational wave antennae. In their present form the resonators constitute small simple sensor elements for a wide range of applications where displacements take place, such as seismometry, gravimetry, thermal expansion measurements, as well as gravitational wave antennae. Radio-frequency losses in the niobium-sapphire interface have been observed. These limit the resonator Q to less than 10(5) and show a strong power dependence. Several methods of fabrication of the niobium-on-sapphire circuits have been investigated. Complete details for construction are given. An accelerometer based on these resonators is described in an accompanying paper.     

煤炭称重销售系统中射频卡的应用与研究

以煤炭称重销售系统中的射频卡开发与应用为基础,探讨煤炭称重销售系统中射频卡的应用原理、射频卡的选用、读写、防冲撞、初始化以及中文字符存储、内容读写及编程的实现方法。     

基于样品点优化的变权重组合软件可靠性的仿真研究

为提高软件可靠性预测精度,本文在建立多种单一软件可靠性预测模型的基础上,提出一种多模型变权重组合模型.实证仿真验证该模型无论在样本内还是样本外都较经过模拟退火算法优化的BP神经网络(SA-BP)及经过遗传算法优化的最小二乘支持向量机(GA-LSVM)较优,说明该变权重组合模型是一种精度更高的软件可靠性失效数据预测模型,具有较好的应用推广价值.     

High power solid state rf amplifier for proton accelerator

A 1.5 kW solid state rf amplifier at 352 MHz has been developed and tested at RRCAT. This rf source for cw operation will be used as a part of rf system of 100 MeV proton linear accelerator. A rf power of 1.5 kW has been achieved by combining output power from eight 220 W rf amplifier modules. Amplifier modules, eight-way power combiner and divider, and directional coupler were designed indigenously for this development. High efficiency, ease of fabrication, and low cost are the main features of this design.     

低场核磁共振射频场屏蔽效能的计算与研究

采用有限元方法计算了圆柱形屏蔽体的屏蔽效能和屏蔽体对螺线管内部磁场的影响，得到屏蔽效能和螺线管内部磁场随屏蔽体尺寸变化的曲线。并用Matlab对球形屏蔽体的屏蔽效能进行了计算，二者基本一致。结果表明，屏蔽效能随圆柱体半径的增加而缓慢增加，随圆柱体厚度的增加而迅速增加，但是当厚度大于1．5mm以后，几乎保持不变。     

Low-dissipation tunable rf preamplifier for low temperature NMR applications

We describe a simple circuit which can be used as an impedance matching device to improve the S/N ratio when lossy cables must be used in low-temperature NMR experiments. The total dissipation is less than 2 mW and the circuit operates satisfactorily down to 1.5 K. The only tuned circuit is the nuclear resonance circuit which incorporates GaAs (P) diodes which can be tuned remotely.