為了提高超高頻RFID系統中閱讀器在低信噪比的情況下仍具有較高的識別能力,提出一種基于FPGA系統結合軟件無線電方法實現超高頻RFID射頻前端電路方案。超高頻射頻識別系統必須符合EPC Class 1generation 2標準,所設計的電路系統以Xilinx公司的XC6SLX16-2CSG324FPGA芯片為硬件基礎,將數字基帶調制解調和中頻濾波電路在FPGA系統中設計實現,重點闡述了射頻前端電路的設計結構、AD/DA轉換電路,以及數字濾波器的設計。實驗結果表明,所設計的超高頻RFID閱讀器簡化了前端電路系統結構,提升了穩定性,增強了抗干擾能力。該電路系統在信噪比較低的情況下,能夠較好地實現915MHz頻率的射頻接收和發送。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...
標簽： 915mhz 超高頻 rfid 閱讀 射頻 前端 電路 設計
上傳時間： 2022-04-17
上傳用戶：shjgzh
超聲波換能器作為一種實用的檢測手段，能實現聲波所攜帶的信息和電能之間轉換。它的性能優良，價格低廉，操作方便，易于調試，因此在工農業生產中發揮著重要的作用。但目前換能器驅動電路的發射頻率多為40 kHz，本文針對1 MHz的超聲波換能器電路進行了設計，主要介紹了它的發射驅動電路和接收驅動電路的設計方案，并對它們的功能進行了詳細地說明。最后搭建實驗平臺，并對電路的輸入、輸出模塊進行了測試。實驗結果表明，換能器電路運行良好，可以為超聲波高精度測量領域的應用提供參考。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...
上傳時間： 2022-04-28
上傳用戶：
數字頻率計是電工電子中常用的測量儀器,數字頻率計通過用輸入待測信號對一特定長度的信號進行計數,從而得出頻率并通過數碼管直觀的顯示出來。本文提出了一種與輸入同步的數字頻率計的設計,提高了頻率計的精度,設計采用Multisim軟件進行設計和仿真的過程,介紹了其工作原理,硬件電路設計和仿真的過程。設計采用了Multisim軟件進行設計和仿真,設計結果得到的驗證。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.
標簽： multisim
上傳時間： 2022-05-08
上傳用戶：
說明：1，測試交流電源（Test AC Power Supply）：A.中國（China）：AC 220V+/-2%50Hz+/-2%B.美國（United States of America）：AC 120V+/-2%60Hz+/-2%。C.英國（Britain）：AC 240V+/-2%50Hz+/-2%D.歐洲（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，測試溫度條件（Test Temperature Conditions）：25℃+/-2℃。3，測試以右聲道為準（Standard Test Use Right Channell）4，信號由AUX插座輸入（Signal From AUX Jack Input）。5，測試以音量最大，音調和平衡在中央位置（電子音調在正常狀態）。（Test Volume Setup Max，Equalizer And Balance Setup Center）。6，標準輸出（Standard Output）：A.輸入1 KHz頻率信號（Input 1 KHz Frequency Signal）B.左右聲道輸入信號測試右聲道（L&R Input Signal Test Use R Channel）C.額定輸出功率満（Rating Output Power Full）10 W，標準輸出定為1w.（Rating Output Power Full 10 w，Standard Output Setup 1 W）D.額定輸出功率1W到10w，標準輸出定為500 mW（Rating Output Power 1 W To 10 W，Standard Output Setup 500 mW）E.額定輸出功率小于1w，標準輸出定為50 mW（Rating Output Power Not Full 1 W，Standard Output Setup 50 mW）F.標準輸出電壓以V-VPR為準（Standard Output Voltage Use V-V/PR）。G.V-V/PR中P為額定輸出功率，R為喇叭標稱阻抗。
標簽： 音響功放
上傳時間： 2022-06-18
上傳用戶：
canopen 402協議，運動控制資料，“The CANopen device profile for drives and motion controllers defines the interface to frequency inverters, servo controllers as well as stepper motors.”
標簽： canopen
上傳時間： 2022-06-18
上傳用戶：
移動通信網絡由于帶寬和技術的限制，遠遠不能滿足人們不斷高漲的無線上網需求。Wi-Fi作為無線接入技術MLAN的主流標準口益成熟，它能夠隨時隨地高速連接到Internet，極大地滿足了用戶對無線上網需求，受到消費者的青睞。因而越來越多的移動終端都集成了Wi-Fi功能，Wi-Fi和藍牙樣成為移動終端的標配。隨之而來的是wi-Fi和藍牙都工作在2.4CHZz ISM頻段而引發的互相 擾問題，導致數據吞吐量下降，語音質量惡化失真，極端狀況下甚至導致鏈路斷開而不能正常工作。因此，必須尋求有效的措施和方法，實現兩種技術在近距離的和諧共存，這已成為非常迫切的技術需要，也成為人們研究的一個熱點和難點。近距離WiFi和藍牙互相1擾的問題，目前已經形成了非常多的有效解決機制，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機制在Wi-Fi側MAC層實現，通過協調Wi-Fi和藍牙的幀發射時間來避免相互干擾：而DSE是在Wi-Fi側物理層PHY實現，通過一個可編程帶阻濾波器（Notch Filter）來阻止來白藍牙的窄帶干擾。還有基于藍牙側的AFH（Adaptive Frequency Hopping），它通過跳頻，自動避開被干擾的頻點，從而大大提高了藍牙傳輸性能。
上傳時間： 2022-06-20
上傳用戶：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
標簽： EMC
上傳時間： 2022-06-29
上傳用戶：d1997wayne
5GNR信道編碼研究，信道編碼是 5G 的關鍵技術之一，描述了 5G 新空口（NR——New Radio Access）的低密度奇偶校驗碼（LDPCC——Low Density Parity Check Codes）和 極化碼（Polar Codes）的關鍵技術；通過仿真，比較了5G NR的信道編碼方案與 4G LTE信道編碼方案的性能。另外，還比較了這2代信道編碼技術的復雜度和 吞吐量。
標簽： 信道編碼
上傳時間： 2022-06-30
上傳用戶：
摘要：本系統以ICL8038集成塊為核心器件，制作一種函數信號發生器，制作成本較低。適合學生學習電子技術測量使用。ICL8038是一種具有多種波形輸出的精密振蕩集成電路，只需要個別的外部元件就能產生從0.001Hz~30KlHz的低失真正弦波、三角波、矩形波等脈沖信號。輸出波形的頻率和占空比還可以由電流或電阻控制。另外由于該芯片具有調制信號輸入端，所以可以用來對低頻信號進行頻率調制。關鍵詞：函數信號發生器頻率調制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.
上傳時間： 2022-07-04
上傳用戶：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
上傳時間： 2022-07-08
上傳用戶：
