One of the prerequisites for the development of telecommunication services is the understanding of the propagation of the Waves, either acoustic, electromagnetic, radio or light Waves, which are used for the transmission of information. In this work, we shall limit ourselves to the study of radio Waves: this term apply to the electromagnetic Waves used in radio communications. Their frequency spectrum is very broad, and is divided into the following frequency bands : ELF Waves (f < 3 kHz), VLF (3-30 kHz), LF Waves (30-300 kHz), MF Waves (300-3000 kHz), HF (3-30 MHz), VHF Waves (30-300 MHz), UHF Waves (300-3000 MHz), SHF Waves (3-30 GHz), EHF Waves (30-300 GHz) and sub- EHF Waves (300-3000 GHz).
標簽： Propagation Radio Wave
上傳時間： 2020-06-01
上傳用戶：shancjb
The unguided transmission of information using electromagnetic Waves at radio frequency (RF) is often referred to as wireless communications, the first demonstration of which took place at the end of the 19th cen- tury and is attributed to Hertz. The technology was, shortly thereafter, commercialised by, amongst others, Marconi in one of the first wire- less communication systems, i.e., wireless telegraphy. In the first half of the 20th century the technology was developed further to enable more than the mere transmission of Morse code. This first resulted in uni- directional radio broadcasting and several years later also in television broadcasting.
標簽： Imperfections RF
上傳時間： 2020-06-01
上傳用戶：shancjb
There is an unprecedented enthusiasm for radio frequency identification (RFID) technologies today. RFID is based on the exchange of information carried by electromagnetic Waves between a label, or tag, and a reader. This technology is currently in full economic expansion, which has manifested itself in widely backed research activities, some of which will be examined in this book.
標簽： Identification Frequency Sensors Radio and
上傳時間： 2020-06-08
上傳用戶：shancjb
基于TMS320F28035芯片為控制核心的空間矢量異步電機變頻器 我們設計的異步電機變頻調速器以TMS320F28035芯片為控制核心，通過輸出三相PWM波控制智能功率模塊IPM驅動三相異步電機。我們使用空間矢量SVPWM算法，并對其進行了優化。采用檢測反電勢的方法省去了昂貴的光電編碼器，大大節省了成本。同時開創性的研發了自動根據運行環境調節的自適應變頻算法，使我們的變頻調速器可以在電網條件惡劣的鄉村山區工作，由此該變頻器已被一家民用水泵生產企業預訂。關鍵字 變頻器 TMS320f28035 IPM SVPWM In our design, the asynchronous machine inverter based on the chip of TMS320F28035 drives the three-Phase asynchronous machine by sending three-phase PWM Waves to the IPM, which is short for the Intelligent-Power-Module. The SVPWM (space vector pulse width modulation) strategy is applied to our control algorithm and we optimize it mainly in two aspects. Firstly the inverter detects the speed by measuring the Back EMF instead of installing an expensive photoelectric encoder for costs reduction.
標簽： tms320f28035 芯片
上傳時間： 2022-05-08
上傳用戶：zhanglei193
VIP專區-嵌入式/單片機編程源碼精選合集系列（76）資源包含以下內容：1. stc12c的AD處理.2. 這是keil公司的mcm2300開發板上的.3. 一些關于SOPC,NIOS設計的論文,可以作畢業設計參考.4. 遠程數據訪問RDA等.5. 基于lpc2148的按鍵掃描程序.6. spce061a實現的鍵盤掃描程序.7. SPCE061A實現的LED拉幕顯示效果.8. SPCE061A中位操作頭文件.9. SPCE061A+SPCL051液晶顯示漢字程序.10. keil.11. 采用LPC935控制的一個項目.12. 采用MPS430控制的項目.13. mm36sb020的spi的接口,已經調試過的 /* 定義命令 *//* #define ERSC 0x90f6 // 檫除整個芯片 // #define SRC 0xfffffffe //.14. LCD6963模塊的驅動,可以顯示漢字和圖形. 線路圖 89C51 T6963C -------- | 8 P1.0-1.7|=========== D0-7 | P3.0|--.15. ATmega16上面的ADC測試.16. 小液晶1602驅動程序.17. 基於C51的智能毫秒計, 精準到1ms, 含原理圖.18. NXP2103開發版圖.19. 軟件紅外線接收程序 采用24MHz晶振.20. 串行口通信程序.21. 投票系統.22. 一擔挑游戲.23. 組數游戲.24. 歌星大獎賽.25. VHDL mif file generator, which can generate several Waves.26. uboot.27. 該程序是一個tffs文件系統的源碼.28. 這是一個測試液晶顯示的程序,測試LCD的亮滅.硬件連接如下: 3腳接偏置電阻,接個10K的可調,.RS4,RW5,E6腳接P3^3,P3^2,P3^1,程序頭部有定義可根據實際修改.29. uart5/atmega8515/led 時鐘顯示.30. 逆變器原理圖.31. 基于LPC2210的FFT程序.32. 這是我讀研的時候用VB開發的一個與基于CAN-PCI5121的通訊小程序.33. 這是基于CAN-PCI5121開發的通訊程序.34. 將每一個聲源加到混音緩沖器,經過處理后返回.35. 處理聲源,時間,做好各類資源的調整工作,為聲音的輸入輸出做準備..36. NiosII培訓資料,主要講述如何操作NIOS,對初學者幫助較大..37. 當前流行的802.15.4ZIGBEE協議的應用開發流程.38. Zigbee應用開發介紹說明.39. 完整的空調控制程序.40. VMMforSystemVerilog的源碼資料 學習SystemVerilog的好東西.
上傳時間： 2013-05-19
上傳用戶：eeworm
