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difficulty

  • SDP Search and Record generator OVERVIEW: Recognizing the difficulty in creating an SDP service

    SDP Search and Record generator OVERVIEW: Recognizing the difficulty in creating an SDP service description and search from scratch, Microsoft is providing a sample utility in bthnscreate.cxx to automatically create a service or record. This utility can be run to create an SDP record or to setup an SDP Service, Attribute, or ServiceAttribute search based on information stored in a human readable file.

    标签: Recognizing difficulty SDP generator

    上传时间: 2015-04-16

    上传用户:dyctj

  • Vc++入门的捷径 一些c++的小问题 以及代码大全 maybe something about the difficulty in studying C

    Vc++入门的捷径 一些c++的小问题 以及代码大全 maybe something about the difficulty in studying C

    标签: difficulty something studying maybe

    上传时间: 2016-10-11

    上传用户:fxf126@126.com

  • 扩频通信芯片STEL-2000A的FPGA实现

    针对传统集成电路(ASIC)功能固定、升级困难等缺点,利用FPGA实现了扩频通信芯片STEL-2000A的核心功能。使用ISE提供的DDS IP核实现NCO模块,在下变频模块调用了硬核乘法器并引入CIC滤波器进行低通滤波,给出了DQPSK解调的原理和实现方法,推导出一种简便的引入?仔/4固定相移的实现方法。采用模块化的设计方法使用VHDL语言编写出源程序,在Virtex-II Pro 开发板上成功实现了整个系统。测试结果表明该系统正确实现了STEL-2000A的核心功能。 Abstract:  To overcome drawbacks of ASIC such as fixed functionality and upgrade difficulty, FPGA was used to realize the core functions of STEL-2000A. This paper used the DDS IP core provided by ISE to realize the NCO module, called hard core multiplier and implemented CIC filter in the down converter, described the principle and implementation detail of the demodulation of DQPSK, and derived a simple method to introduce a fixed phase shift of ?仔/4. The VHDL source code was designed by modularity method , and the complete system was successfully implemented on Virtex-II Pro development board. Test results indicate that this system successfully realize the core function of the STEL-2000A.

    标签: STEL 2000 FPGA 扩频通信

    上传时间: 2013-11-05

    上传用户:liu123

  • 基于塑料光纤的高压隔离通信接口设计

     通过比较各种隔离数字通信的特点和应用范围,指出塑料光纤在隔离数字通信中的优势。使用已经标准化的TOSLINK接口,有利于节省硬件开发成本和简化设计难度。给出了塑料光纤的硬件驱动电路,说明设计过程中的注意事项,对光收发模块的电压特性和频率特性进行全面试验,并给出SPI口使用塑料光纤隔离通信的典型应用电路图。试验结果表明,该设计可为电力现场、电力电子及仪器仪表的设计提供参考。 Abstract:  y comparing characteristics and applications area of various isolated digital communications, this article indicates advantages of plastic optical fiber in isolated digital communications. Using the standardized TOSLINK interface, it helps to control costs and difficulty in hardware development and design. Then it gives the hardware driver circuit of plastic optical fiber module, explains the noticed details in design process, gives results on the basis of the optical transceiver module voltage characteristics and frequency characteristics tests. Finally,it gives typical application circuit of the SPI communication port by using plastic optical fiber isolation .The results show that this design can be referenced for the power field, power electronics and instrumentation design.

    标签: 塑料光纤 高压隔离 通信 接口设计

    上传时间: 2014-01-10

    上传用户:gundan

  • 快速跳频通信系统同步技术研究

    同步技术是跳频通信系统的关键技术之一,尤其是在快速跳频通信系统中,常规跳频通信通过同步字头携带相关码的方法来实现同步,但对于快跳频来说,由于是一跳或者多跳传输一个调制符号,难以携带相关码。对此引入双跳频图案方法,提出了一种适用于快速跳频通信系统的同步方案。采用短码携带同步信息,克服了快速跳频难以携带相关码的困难。分析了同步性能,仿真结果表明该方案同步时间短、虚警概率低、捕获概率高,同步性能可靠。 Abstract:  Synchronization is one of the key techniques to frequency-hopping communication system, especially in the fast frequency hopping communication system. In conventional frequency hopping communication systems, synchronization can be achieved by synchronization-head which can be used to carry the synchronization information, but for the fast frequency hopping, Because modulation symbol is transmitted by per hop or multi-hop, it is difficult to carry the correlation code. For the limitation of fast frequency hopping in carrying correlation code, a fast frequency-hopping synchronization scheme with two hopping patterns is proposed. The synchronization information is carried by short code, which overcomes the difficulty of correlation code transmission in fast frequency-hopping. The performance of the scheme is analyzed, and simulation results show that the scheme has the advantages of shorter synchronization time, lower probability of false alarm, higher probability of capture and more reliable of synchronization.

    标签: 快速跳频 同步技术 通信系统

    上传时间: 2013-11-23

    上传用户:mpquest

  • 扩频通信芯片STEL-2000A的FPGA实现

    针对传统集成电路(ASIC)功能固定、升级困难等缺点,利用FPGA实现了扩频通信芯片STEL-2000A的核心功能。使用ISE提供的DDS IP核实现NCO模块,在下变频模块调用了硬核乘法器并引入CIC滤波器进行低通滤波,给出了DQPSK解调的原理和实现方法,推导出一种简便的引入?仔/4固定相移的实现方法。采用模块化的设计方法使用VHDL语言编写出源程序,在Virtex-II Pro 开发板上成功实现了整个系统。测试结果表明该系统正确实现了STEL-2000A的核心功能。 Abstract:  To overcome drawbacks of ASIC such as fixed functionality and upgrade difficulty, FPGA was used to realize the core functions of STEL-2000A. This paper used the DDS IP core provided by ISE to realize the NCO module, called hard core multiplier and implemented CIC filter in the down converter, described the principle and implementation detail of the demodulation of DQPSK, and derived a simple method to introduce a fixed phase shift of ?仔/4. The VHDL source code was designed by modularity method , and the complete system was successfully implemented on Virtex-II Pro development board. Test results indicate that this system successfully realize the core function of the STEL-2000A.

    标签: STEL 2000 FPGA 扩频通信

    上传时间: 2013-11-19

    上传用户:neu_liyan

  • he AVRcam source files were built using the WinAVR distribution (version 3.3.1 of GCC). I haven t t

    he AVRcam source files were built using the WinAVR distribution (version 3.3.1 of GCC). I haven t tested other versions of GCC, but they should compile without too much difficulty. The makefile used to build the source is included

    标签: distribution version AVRcam WinAVR

    上传时间: 2014-10-25

    上传用户:h886166

  • This approach addresses two difficulties simultaneously: 1) the range limitation of mobile robot se

    This approach addresses two difficulties simultaneously: 1) the range limitation of mobile robot sensors and 2) the difficulty of detecting buildings in monocular aerial images. With the suggested method building outlines can be detected faster than the mobile robot can explore the area by itself, giving the robot an ability to “see” around corners. At the same time, the approach can compensate for the absence of elevation data in segmentation of aerial images. Our experiments demonstrate that ground-level semantic information (wall estimates) allows to focus the segmentation of the aerial image to find buildings and produce a ground-level semantic map that covers a larger area than can be built using the onboard sensors.

    标签: simultaneously difficulties limitation addresses

    上传时间: 2014-06-10

    上传用户:waitingfy

  • The AVRcam source files were built using the WinAVR distribution (version 3.3.1 of GCC). I haven t

    The AVRcam source files were built using the WinAVR distribution (version 3.3.1 of GCC). I haven t tested other versions of GCC, but they should compile without too much difficulty. * The source files for the AVRcam had the author name and copyright information added back into them after the judging of the project, since it states in the competition rules that the author s name can not be present during their inspection. * The included source files are the ones that were submitted for the entry into the Circuit Cellar contest. I have continued to develop the AVRcam, and have added several new features (such as ignoring objects that aren t larger than a minimum size, removing tracked objects that overlap with each, and some general optimizations). If you are interested in the latest source, email me at john@jrobot.net * For more info about the AVRcam, check out http://www.jrobot.net John Orlando August 20, 2004

    标签: distribution version AVRcam source

    上传时间: 2016-12-30

    上传用户:GavinNeko

  • Digital+Communication+over+Fading+Channels 1st

    Regardless of the branch of science or engineering, theoreticians have always been enamored with the notion of expressing their results in the form of closed-form expressions. Quite often, the elegance of the closed-form solution is overshadowed by the complexity of its form and the difficulty in evaluating it numerically. In such instances, one becomes motivated to search instead for a solution that is simple in form and simple to evaluate. 

    标签: Communication Channels Digital Fading over 1st

    上传时间: 2020-05-27

    上传用户:shancjb