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.
上传时间： 2013-10-18
上传用户：myworkpost
Radio frequency (RF) can be a complex subject to navigate, but it does not have to be. If you are just getting started with radios or maybe you cannot find that old reference book about antenna aperture, this guide can help. It is intended to provide a basic understanding of RF technology, as well act as a quick reference for those who “know their stuff” but may be looking to brush up on that one niche term that they never quite understood. This document is also a useful reference for Maxim’s products and data sheets, an index to deeper analysis found in our application notes, and a general reference for all things RF.
上传时间： 2013-10-23
上传用户：685
Radio frequency (RF) can be a complex subject to navigate, but it does not have to be. If you are just getting started with radios or maybe you cannot find that old reference book about antenna aperture, this guide can help. It is intended to provide a basic understanding of RF technology, as well act as a quick reference for those who “know their stuff” but may be looking to brush up on that one niche term that they never quite understood. This document is also a useful reference for Maxim’s products and data sheets, an index to deeper analysis found in our application notes, and a general reference for all things RF.
标签： 无线技术
上传时间： 2013-10-08
上传用户：kinochen
Abstract: This application note illustrates the flexibility of the MAX7060 ASK/FSK transmitter. While the currently available evaluationkit (EV kit) has been optimized for the device's use in a specific frequency band (i.e., 288MHz to 390MHz), this document addresseshow the EV kit circuitry can be modified for improved operation at 433.92MHz, a frequency commonly used in Europe. Twoalternative match and filter configurations are presented: one for optimizing drain efficiency, the other for achieving higher transmitpower. Features and capabilities of earlier Maxim industrial, scientific, and medical radio-frequency (ISM-RF) transmitters areprovided, allowing comparison of the MAX7060 to its predecessors. Several design guidelines and cautions for using the MAX7060are discussed.
上传时间： 2013-11-14
上传用户：swaylong
提出了一种基于PIC16F877A微控制器和CC2500射频收发器芯片的低功耗、低成本RFID（Radio Frequency Identification， 无线射频识别）局域定位系统设计方法，介绍了系统的定位工作原理、主要硬件电路模块及定位算法的设计和实现。采用基于序列号对时隙数运算的排序算法有效解决了多标签识别碰撞的问题，基于射频辐射强度（Received Signal Strength Indication， RSSI）和圆周定位算法实现了基于RFID多标签系统的平面定位。实验测试表明，这种射频定位方法能够实现一定精度下的无线局域定位的功能。
上传时间： 2013-11-06
上传用户：weareno2
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。
上传时间： 2013-11-19
上传用户：moshushi0009
Radio Frequency Identifi cation (RFID) technology usesradiated and refl ected RF power to identify and track avariety of objects. A typical RFID system consists of areader and a transponder (or tag). An RFID reader containsan RF transmitter, one or more antennas and an RFreceiver. An RFID tag is simply an uniquely identifi ed ICwith an antenna.
上传时间： 2013-10-17
上传用户：lepoke
Abstract: Engineers often wish that radio susceptibility (RS) or radio immunity could be cured with an antibiotic, a vaccine, or someform of cure-all. Unfortunately, solving the RS problem is not that easy. Indeed, the laws of physics apply. In this article we discusssources of RS. We also offer tips and hints to protect systems, power supplies, printed circuit boards (PCBs), and electroniccomponents from radio frequency interference.
标签： Susceptibility Radio 无线电干扰
上传时间： 2014-12-30
上传用户：旗鱼旗鱼
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.
上传时间： 2013-10-30
上传用户：swaylong
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.
上传时间： 2014-01-10
上传用户：gundan
