It is more than a decade since GSM was first commercially available. After some unexpected delay, it seems that finally UMTS is here to stay as a 3G system standardised by 3GPP, at least for another ten years. UMTS will enable multi-service, multi-rate and flexible IP native-based mobile technologies to be used in wide area scenarios and also pave the way for a smooth transition from circuit switched voice networks to mobile packet services.
標簽： Management Strategies Resource Radio
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
The radio spectrum is one of the most precious resources which must be managed to ensure efficient access for the wireless communication services which use it. The allocation and management of spectrum are administered by the regulatory authorities. Traditionally, spectrum allocation is carried out exclusively of its use in large geographic areas and assigning frequency bands to specific users or service providers is proved to be inefficient. Recently, substantial knowledge about dynamic spectrum access scheme has been accumulated to enable efficient spectrum sharing.
標簽： Management Spectrum Access and
上傳時間： 2020-06-01
上傳用戶：shancjb
The continuing vitality of spread-spectrum communication systems and the devel- opment of new mathematical methods for their analysis provided the motivation to undertake this new edition of the book. This edition is intended to enable readers to understand the current state-of-the-art in this field. Almost twenty percent of the materialinthiseditionisnew, includingseveralnewsections, anewchapteronadap- tive arrays and filters, and a new chapter on code-division multiple-access networks. The remainder of the material has been thoroughly revised, and I have removed a considerable amount of material that has been superseded by more definitive results.
標簽： Spread-Spectrum Communication Systems 3rd
上傳時間： 2020-06-01
上傳用戶：shancjb
Second-generation telecommunication systems, such as the Global System for Mobile Communications (GSM), enabled voice traffic to go wireless: the number of mobile phones exceeds the number of landline phones and the mobile phone penetration is approaching 100% in several markets. The data-handling capabilities of second-generation systems are limited, however, and third-generation systems are needed to provide the high bit-rate services that enable high-quality images and video to be transmitted and received, and to provide access to the Web with higher data rates.
標簽： Evolution WCDMA UMTS HSPA LTE for and
上傳時間： 2020-06-01
上傳用戶：shancjb
Wireless Mesh Networks (WMN) are believed to be a highly promising technology and will play an increasingly important role in future generation wireless mobile networks. WMN is characterized by dynamic self-organization, self-configuration and self-healing to enable quick deployment, easy maintenance, low cost, high scalability and reliable services, as well as enhancing network capacity, connect- ivity and resilience.
標簽： Networking Wireless Mesh
上傳時間： 2020-06-01
上傳用戶：shancjb
The continuous progress in modern power device technology is increasingly supported by power-specific modeling methodologies and dedicated simulation tools. These enable the detailed analysis of operational principles on the the device and on the system level; in particular, they allow the designer to perform trade- off studies by investigating the operation of competing design variants in a very early stage of the development process. Furthermore, using predictive computer simulation makes it possible to analyze the device and system behavior not only under regularoperatingconditions, but also at the rim of the safe-operatingarea and beyond of it, where destructive processes occur that limit the lifetime of a power system.
標簽： POWERHVMOS_Devices_Compact_Modeli ng
上傳時間： 2020-06-07
上傳用戶：shancjb
RFID is at a critical price point that could enable its large-scale adoption. What strengths are pushing it forward? What technical challenges and privacy concerns must we still address?
標簽： an-introduction-to-rfid-technolog
上傳時間： 2020-06-08
上傳用戶：shancjb
With all the recent hype over radio frequency identification (RFID) and the requirements to implement it, you might think that RFID can turn water into wine, transform lead into gold, and cure the world’s diseases. You might also be worried that RFID will enable Big Brother to track your move- ments to within a foot of your location from a satellite five hundred miles up in space. The truth is, RFID can do none of these things. In this chapter, you find out the basics of what RFID is, what forces are dri- ving RFID as a replacement for the bar code in the marketplace, and what benefits RFID can offer
標簽： ForDummies_RFID_For_Dummies
上傳時間： 2020-06-08
上傳用戶：shancjb
lm75A溫度數字轉換器 FPGA讀寫實驗Verilog邏輯源碼Quartus工程文件+文檔資料,FPGA為CYCLONE4系列中的EP4CE6E22C8. 完整的工程文件，可以做為你的學習設計參考。LM75A 是一個使用了內置帶隙溫度傳感器和模數轉換技術的溫度數字轉換器。它也是一個溫度檢測器，可提供一個過熱檢測輸出。LM75A 包含許多數據寄存器：配置寄存器用來存儲器件的某些配置，如器件的工作模式、OS 工作模式、OS 極性和OS 故障隊列等（在功能描述一節中有詳細描述）；溫度寄存器（Temp），用來存儲讀取的數字溫度；設定點寄存器（Tos & Thyst），用來存儲可編程的過熱關斷和滯后限制，器件通過2 線的串行I2C 總線接口與控制器通信。LM75A 還包含一個開漏輸出（OS），當溫度超過編程限制的值時該輸出有效。LM75A 有3 個可選的邏輯地址管腳，使得同一總線上可同時連接8個器件而不發生地址沖突。LM75A 可配置成不同的工作條件。它可設置成在正常工作模式下周期性地對環境溫度進行監控或進入關斷模式來將器件功耗降至最低。OS 輸出有2 種可選的工作模式：OS 比較器模式和OS 中斷模式。OS 輸出可選擇高電平或低電平有效。故障隊列和設定點限制可編程，為了激活OS 輸出，故障隊列定義了許多連續的故障。溫度寄存器通常存放著一個11 位的二進制數的補碼，用來實現0.125℃的精度。這個高精度在需要精確地測量溫度偏移或超出限制范圍的應用中非常有用。正常工作模式下，當器件上電時，OS 工作在比較器模式，溫度閾值為80℃，滯后75℃，這時，LM75A就可用作一個具有以上預定義溫度設定點的獨立的溫度控制器。module LM75_SEG_LED ( //input input sys_clk ,input sys_rst_n ,inout sda_port ,//output output wire seg_c1 ,output wire seg_c2 ,output wire seg_c3 ,output wire seg_c4 ,output reg seg_a ,output reg seg_b ,output reg seg_c ,output reg seg_e ,output reg seg_d ,output reg seg_f ,output reg seg_g ,output reg seg_h , output reg clk_sclk );//parameter define parameter WIDTH = 8;parameter SIZE = 8;//reg define reg [WIDTH-1:0] counter ;reg [9:0] counter_div ;reg clk_50k ;reg clk_200k ;reg sda ;reg enable ;
上傳時間： 2021-10-27
上傳用戶：
