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RADIO-Frequency

  • 机电类比法在传感器中的相关分析

    机电类比法是一种把机械量通过一定的计算等效类比为电量的方法,其在对电子机械系统的分析中应用非常广泛。它能够把一个较复杂的机械系统类比为我们熟知的电路系统来进行分析,从而使问题的分析得到简化。本文通过对振弦式传感器的分析介绍了机电类比法,并对使用电路进行了相关的分析。 Summary:The electromechanical analogy is assort of analysis which is to analogize the mechanical system by using circuit system , it applied widely in the filed of analysis the electronic-mechanical system. The analysis can take a complex mechanical system analogous to a circuitry that we well-known, which can simplify the problems. In the paper, the electro-mechanical analogy method is briefly introduced by analysis the vibrating wire sensor,and have a correlation analysis about the circuit we used.关键词: 机电类比法  振弦式传感器  频率  振荡  反馈Keyword:electro-mechanical analogy method,vibrating wire sensor,frequency,  oscillation, feedback 0  引言振弦式传感器是属于频率式传感器的一种。所谓频率式传感器就是能直接将被测量转换为振动频率信号的传感器,这类传感器一般是通过测量振弦、振筒、振梁、振膜等弹性振体或石英晶体谐振器的固有谐振频率来达到测量引起谐振频率变化的被测非电量的目的,其也称为谐振式传感器[1]。在分析该类传感器中,由于其涉及到频率,就容易让人联想到在电子技术中接触到的RLC振荡电路。因此可以尝试着用类比的方法使之对应起来分析,即机电类比法分析。

    标签: 机电 传感器 类比法

    上传时间: 2013-11-16

    上传用户:paladin

  • CC1110:RF 片上系统解决方案

    The CC1101 is a low-cost sub- 1 GHztransceiver designed for very low-powerwireless applications. The circuit is mainlyintended for the ISM (Industrial, Scientific andMedical) and SRD (Short Range Device)frequency bands at 315, 433, 868, and 915MHz, but can easily be programmed foroperation at other frequencies in the 300-348MHz, 387-464 MHz and 779-928 MHz bands.CC1101 is an improved and code compatibleversion of the CC1100 RF transceiver. Themain improvements on the CC1101 include:

    标签: 1110 CC 片上系统 方案

    上传时间: 2013-11-12

    上传用户:363186

  • 移动无线终端导航AFE和数据转换器

    Abstract: High-speed and low-speed data converters serve critical functions in modern broadband mobile radios. This application note outlines how todetermine high-speed data converter performance requirements in baseband sampling radio architectures. Also, system partition strategies andadvantages are outlined when considering a high-speed analog front-end (AFE) solution.

    标签: AFE 移动 无线终端 导航

    上传时间: 2013-11-02

    上传用户:jjj0202

  • 克服了正交频分复用(OFDM)和IEEE 1901.2智能电网通信的挑战

    Abstract: While many questions still surround the creation and deployment of the smart grid, the need for a reliablecommunications infrastructure is indisputable. Developers of the IEEE 1901.2 standard identified difficult channel conditionscharacteristic of low-frequency powerline communications and implemented an orthogonal frequency division multiplexing (OFDM)architecture using advanced modulation and channel-coding techniques. This strategy helped to ensure a robust communicationsnetwork for the smart grid.

    标签: 1901.2 OFDM IEEE 正交频分复用

    上传时间: 2013-10-18

    上传用户:myworkpost

  • 降低OFDM信号PAPR的方法研究

    正交频分复用 (Orthogonal Frequency Division Multiplexing,OFDM)是一种多载波调制技术,由于具有良好的抗多径干扰性能,适用于高速数据传输,OFDM成为近年来人们研究的热点。但是其峰均比较高,应用受到了限制,因此有必要研究降低PAPR的方法。本文首先介绍了OFDM的基本原理和PAPR的基本概念,然后讨论了目前常用的降低PAPR的方法,最后对SLM和PTS方法进行了MATLAB仿真。

    标签: OFDM PAPR 信号 方法研究

    上传时间: 2013-11-19

    上传用户:moshushi0009

  • 基于ZigBee技术的无线智能家用燃气报警系统

    在研究传统家用燃气报警器的基础上,以ZigBee协议为平台,构建mesh网状网络实现网络化的智能语音报警系统。由于传感器本身的温度和实际环境温度的影响,传感器标定后采用软件补偿方法。为了减少系统费用,前端节点采用半功能节点设备,路由器和协调器采用全功能节点设备,构建mesh网络所形成的家庭内部报警系统,通过通用的电话接口连接到外部的公用电话网络,启动语音模块进行报警。实验结果表明,在2.4 GHz频率下传输,有墙等障碍物的情况下,节点的传输距离大约为35 m,能够满足家庭需要,且系统工作稳定,但在功耗方面仍需进一步改善。 Abstract:  On the basis of studying traditional household gas alarm system, this paper proposed the platform for the ZigBee protocol,and constructed mesh network to achieve network-based intelligent voice alarm system. Because of the sensor temperature and the actual environment temperature, this system design used software compensation after calibrating sensor. In order to reduce system cost, semi-functional node devices were used as front-end node, however, full-function devices were used as routers and coordinator,constructed alarm system within the family by building mesh network,connected to the external public telephone network through the common telephone interface, started the voice alarm module. The results indicate that nodes transmit about 35m in the distance in case of walls and other obstacles by 2.4GHz frequency transmission, this is able to meet family needs and work steadily, but still needs further improvement in power consumption.

    标签: ZigBee 无线智能 报警系统

    上传时间: 2013-10-30

    上传用户:swaylong

  • 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

  • 差分電路中單端及混合模式S-參數的使用

    Single-Ended and Differential S-Parameters Differential circuits have been important incommunication systems for many years. In the past,differential communication circuits operated at lowfrequencies, where they could be designed andanalyzed using lumped-element models andtechniques. With the frequency of operationincreasing beyond 1GHz, and above 1Gbps fordigital communications, this lumped-elementapproach is no longer valid, because the physicalsize of the circuit approaches the size of awavelength.Distributed models and analysis techniques are nowused instead of lumped-element techniques.Scattering parameters, or S-parameters, have beendeveloped for this purpose [1]. These S-parametersare defined for single-ended networks. S-parameterscan be used to describe differential networks, but astrict definition was not developed until Bockelmanand others addressed this issue [2]. Bockelman’swork also included a study on how to adapt single-ended S-parameters for use with differential circuits[2]. This adaptation, called “mixed-mode S-parameters,” addresses differential and common-mode operation, as well as the conversion betweenthe two modes of operation.This application note will explain the use of single-ended and mixed-mode S-parameters, and the basicconcepts of microwave measurement calibration.

    标签: 差分電路 單端 模式

    上传时间: 2014-03-25

    上传用户:yyyyyyyyyy

  • S参数的设计与应用

    Agilent AN 154 S-Parameter Design Application Note S参数的设计与应用 The need for new high-frequency, solid-state circuitdesign techniques has been recognized both by microwaveengineers and circuit designers. These engineersare being asked to design solid state circuitsthat will operate at higher and higher frequencies.The development of microwave transistors andAgilent Technologies’ network analysis instrumentationsystems that permit complete network characterizationin the microwave frequency rangehave greatly assisted these engineers in their work.The Agilent Microwave Division’s lab staff hasdeveloped a high frequency circuit design seminarto assist their counterparts in R&D labs throughoutthe world. This seminar has been presentedin a number of locations in the United States andEurope.From the experience gained in presenting this originalseminar, we have developed a four-part videotape, S-Parameter Design Seminar. While the technologyof high frequency circuit design is everchanging, the concepts upon which this technologyhas been built are relatively invariant.The content of the S-Parameter Design Seminar isas follows:

    标签: S参数

    上传时间: 2013-12-19

    上传用户:aa54