为了提高超高频RFID系统中阅读器在低信噪比的情况下仍具有较高的识别能力,提出一种基于FPGA系统结合软件无线电方法实现超高频RFID射频前端电路方案。超高频射频识别系统必须符合EPC Class 1generation 2标准,所设计的电路系统以Xilinx公司的XC6SLX16-2CSG324FPGA芯片为硬件基础,将数字基带调制解调和中频滤波电路在FPGA系统中设计实现,重点阐述了射频前端电路的设计结构、AD/DA转换电路,以及数字滤波器的设计。实验结果表明,所设计的超高频RFID阅读器简化了前端电路系统结构,提升了稳定性,增强了抗干扰能力。该电路系统在信噪比较低的情况下,能够较好地实现915MHz频率的射频接收和发送。In order to improve the reader UHF RFID system still has a higher ability to identify,in the case of low signal-to-noise ratio.The UHF RFID systems must comply with EPC Class 1 generation 2 standard.In this paper,the design of the circuit system based on Xilinx＇s XC6SLX16-2CSG324 FPGA chip,and presents UHF RFID RF front-end circuit with software radio based on FPGA system.Digital baseband modem and IF filter circuit is designed and implemented in the FPGA system,and focused on designing the structure of the RF front-end circuit,AD/DA conversion circuits,and digital filter.Experimental results show that the UHF RFID reader de...
标签： 915mhz 超高频 rfid 阅读 射频 前端 电路 设计
上传时间： 2022-04-17
上传用户：shjgzh
超声波换能器作为一种实用的检测手段，能实现声波所携带的信息和电能之间转换。它的性能优良，价格低廉，操作方便，易于调试，因此在工农业生产中发挥着重要的作用。但目前换能器驱动电路的发射频率多为40 kHz，本文针对1 MHz的超声波换能器电路进行了设计，主要介绍了它的发射驱动电路和接收驱动电路的设计方案，并对它们的功能进行了详细地说明。最后搭建实验平台，并对电路的输入、输出模块进行了测试。实验结果表明，换能器电路运行良好，可以为超声波高精度测量领域的应用提供参考。As a practical means of detection, ultrasonic transducer can realize the conversion between theinformation carried by sound wave and electric energy.It has the advantages of excellent performance,low cost, convenient operation and debugging, so plays an important role in industrial and agriculturalproduction.However, the transmitting frequency of the driving circuit for most transducer is 40 kHz.Thecircuit of 1 MHz ultrasonic transducer is designed In this paper. It mainly introduces the emissive drivingcircuit and the receiving circuit design and the detailed function of them. Finally, the experimentalplatform is built, and the circuit of input and output were tested. Experiments show that the transducer＇ s...
上传时间： 2022-04-28
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数字频率计是电工电子中常用的测量仪器,数字频率计通过用输入待测信号对一特定长度的信号进行计数,从而得出频率并通过数码管直观的显示出来。本文提出了一种与输入同步的数字频率计的设计,提高了频率计的精度,设计采用Multisim软件进行设计和仿真的过程,介绍了其工作原理,硬件电路设计和仿真的过程。设计采用了Multisim软件进行设计和仿真,设计结果得到的验证。Digital frequency counter is used to measure the frequency of a signal.It is common to use a multivibrator to generate a standard 1 second time base signal and count input signal gated by this signal.However,the asynchronous of this time base signal with input signal will bring errors.In this paper,a high precision frequency counter which use synchronized time base signal generator is proposed.This frequency counter is designed and simulated by Multisim tools and result is verified.
标签： multisim
上传时间： 2022-05-08
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說明：1，测试交流电源（Test AC Power Supply）：A.中国（China）：AC 220V+/-2%50Hz+/-2%B.美国（United States of America）：AC 120V+/-2%60Hz+/-2%。C.英国（Britain）：AC 240V+/-2%50Hz+/-2%D.欧洲（Europe）：AC 230V+/-2%50Hz+/-2%E.日本（Japan）：AC 100V+/-2%60Hz+/-2%F.墨西哥（Mexico）：AC 127V+/-2%60Hz+/-2%2，测试温度条件（Test Temperature Conditions）：25℃+/-2℃。3，测试以右声道为准（Standard Test Use Right Channell）4，信号由AUX插座输入（Signal From AUX Jack Input）。5，测试以音量最大，音调和平衡在中央位置（电子音调在正常状态）。（Test Volume Setup Max，Equalizer And Balance Setup Center）。6，标准輸出（Standard Output）：A.输入1 KHz频率信号（Input 1 KHz Frequency Signal）B.左右声道输入信号测试右声道（L&R Input Signal Test Use R Channel）C.额定输出功率満（Rating Output Power Full）10 W，标准输出定为1w.（Rating Output Power Full 10 w，Standard Output Setup 1 W）D.额定输出功率1W到10w，标准输出定为500 mW（Rating Output Power 1 W To 10 W，Standard Output Setup 500 mW）E.额定输出功率小于1w，标准输出定为50 mW（Rating Output Power Not Full 1 W，Standard Output Setup 50 mW）F.标准輸出电压以V-VPR为准（Standard Output Voltage Use V-V/PR）。G.V-V/PR中P为额定输出功率，R为喇叭标称阻抗。
标签： 音响功放
上传时间： 2022-06-18
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canopen 402协议，运动控制资料，“The CANopen device profile for drives and motion controllers defines the interface to frequency inverters, servo controllers as well as stepper motors.”
标签： canopen
上传时间： 2022-06-18
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移动通信网络由于带宽和技术的限制，远远不能满足人们不断高涨的无线上网需求。Wi-Fi作为无线接入技术MLAN的主流标准口益成熟，它能够随时随地高速连接到Internet，极大地满足了用户对无线上网需求，受到消费者的青睐。因而越来越多的移动终端都集成了Wi-Fi功能，Wi-Fi和蓝牙样成为移动终端的标配。随之而来的是wi-Fi和蓝牙都工作在2.4CHZz ISM频段而引发的互相 扰问题，导致数据吞吐量下降，语音质量恶化失真，极端状况下甚至导致链路断开而不能正常工作。因此，必须寻求有效的措施和方法，实现两种技术在近距离的和谐共存，这已成为非常迫切的技术需要，也成为人们研究的一个热点和难点。近距离WiFi和蓝牙互相1扰的问题，目前已经形成了非常多的有效解决机制，包括基于Wi-Fi的PTA（Packet Traffic Arbitration）、AWMA（Alternating Wireless Medium Access）和DSE（Deterministic Spectral Excision），其中PTA和AWMA机制在Wi-Fi側MAC层实现，通过协调Wi-Fi和蓝牙的帧发射时间来避免相互干扰：而DSE是在Wi-Fi侧物理层PHY实现，通过一个可编程带阻滤波器（Notch Filter）来阻止来白蓝牙的窄带干扰。还有基于蓝牙侧的AFH（Adaptive Frequency Hopping），它通过跳频，自动避开被干扰的频点，从而大大提高了蓝牙传输性能。
上传时间： 2022-06-20
上传用户：zhanglei193
CISPR 25:2016 Vehicles, boats and internal combustion engines - Radio disturbance characteristics - Limits and methods of measurement for the protection of on-board receivers
标签： EMC
上传时间： 2022-06-29
上传用户：d1997wayne
5GNR信道编码研究，信道编码是 5G 的关键技术之一，描述了 5G 新空口（NR——New Radio Access）的低密度奇偶校验码（LDPCC——Low Density Parity Check Codes）和 极化码（Polar Codes）的关键技术；通过仿真，比较了5G NR的信道编码方案与 4G LTE信道编码方案的性能。另外，还比较了这2代信道编码技术的复杂度和 吞吐量。
标签： 信道编码
上传时间： 2022-06-30
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摘要：本系统以ICL8038集成块为核心器件，制作一种函数信号发生器，制作成本较低。适合学生学习电子技术测量使用。ICL8038是一种具有多种波形输出的精密振荡集成电路，只需要个别的外部元件就能产生从0.001Hz~30KlHz的低失真正弦波、三角波、矩形波等脉冲信号。输出波形的频率和占空比还可以由电流或电阻控制。另外由于该芯片具有调制信号输入端，所以可以用来对低频信号进行频率调制。关键词：函数信号发生器频率调制Abstract：The system ICL8038 integrated block as the core device，producing a kind of function signal generator，producing low cost.Suitable for students to learn the use of electronic technology measurement.ICL8038 is a kind of multi-precision oscillator waveform output integrated circuits，a separate external components only need to be able to generate from the 0.001Hz ~30KHz low-distortion sine wave，triangle wave，square wave pulse signal，etc..Output waveform of the frequency and duty cycle can also be controlled by a currentor resistance.In addition，as the chip has a modulated signal input terminal，it can be used to low-frequency signal is frequency modulation.
上传时间： 2022-07-04
上传用户：zhanglei193
PrefaceDuring the past years, there has been a quickly rising interest in radio access technologies for providingmobile as well as nomadic and fixed services for voice, video, and data. The difference indesign, implementation, and use between telecom and datacom technologies is also becoming moreblurred. One example is cellular technologies from the telecom world being used for broadband dataand wireless LAN from the datacom world being used for voice-over IP.Today, the most widespread radio access technology for mobile communication is digital cellular,with the number of users passing 5 billion by 2010, which is more than half of the world’s population.It has emerged from early deployments of an expensive voice service for a few car-borne users,to today’s widespread use of mobile-communication devices that provide a range of mobile servicesand often include camera, MP3 player, and PDA functions. With this widespread use and increasinginterest in mobile communication, a continuing evolution ahead is foreseen.This book describes LTE, developed in 3GPP (Third Generation Partnership Project) and providingtrue 4G broadband mobile access, starting from the first version in release 8 and through the continuingevolution to release 10, the latest version of LTE. Release 10, also known as LTE-Advanced,is of particular interest as it is the major technology approved by the ITU as fulfilling the IMTAdvancedrequirements. The description in this book is based on LTE release 10 and thus provides acomplete description of the LTE-Advanced radio access from the bottom up.Chapter 1 gives the background to LTE and its evolution, looking also at the different standardsbodies and organizations involved in the process of defining 4G. It also gives a discussion of the reasonsand driving forces behind the evolution.Chapters 2–6 provide a deeper insight into some of the technologies that are part of LTE and itsevolution. Because of its generic nature, these chapters can be used as a background not only for LTEas described in this book, but also for readers who want to understand the technology behind othersystems, such as WCDMA/HSPA, WiMAX, and CDMA2000.Chapters 7–17 constitute the main part of the book. As a start, an introductory technical overviewof LTE is given, where the most important technology components are introduced based onthe generic technologies described in previous chapters. The following chapters provide a detaileddescription of the protocol structure, the downlink and uplink transmission schemes, and the associatedmechanisms for scheduling, retransmission and interference handling. Broadcast operation andrelaying are also described. This is followed by a discussion of the spectrum flexibility and the associated
上传时间： 2022-07-08
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