The rapid growth in mobile communications has led to an increasing demand for wide- band high data rate communications services. In recent years, Distributed Antenna Systems (DAS) has emerged as a promising candidate for future (beyond 3G or 4G) mobile communications, as illustrated by projects such as FRAMES and FuTURE. The architecture of DAS inherits and develops the concepts of pico- or micro-cell systems, where multiple distributed antennas or access points (AP) are connected to and con- trolled by a central unit.
標簽： Distributed Antenna Systems
上傳時間： 2020-05-27
上傳用戶：shancjb
The next-generation wireless broadband technology is changing the way we work, live, learn, and communicate through effective use of state- of-the-art mobile broadband technology. The packet-data-based revolu- tion started around 2000 with the introduction of 1x Evolved Data Only (1xEV-DO) and 1x Evolved Data Voice (1xEV-DV) in 3GPP2 and High Speed Downlink Packet Access (HSDPA) in 3GPP. The wireless broad- band fourth-generation technology (4G) is an evolution of the packet- based 3G system and provides a comprehensive evolution of the Universal Mobile Telecommunications System specifications so as to remain competitive with other broadband systems such as 802.16e (WiMAX)
標簽： Essentials LTE-A LTE and of
上傳時間： 2020-05-27
上傳用戶：shancjb
The first Third Generation Partnership Project (3GPP) Wideband Code Division Multiple Access (WCDMA) networks were launched during 2002. By the end of 2005 there were 100 open WCDMA networks and a total of over 150 operators having frequency licenses for WCDMA operation. Currently, the WCDMA networks are deployedinUniversalMobileTelecommunicationsSystem(UMTS)bandaround2GHz in Europe and Asia including Japan and Korea. WCDMA in America is deployed in the existing 850 and 1900 spectrum allocations while the new 3G band at 1700/2100 is expected to be available in the near future. 3GPP has defined the WCDMA operation also for several additional bands, which are expected to be taken into use during the coming years.
標簽： HSDPAHSUPA Access Speed Radio UMTS High for
上傳時間： 2020-05-27
上傳用戶：shancjb
his research aims at creating broadband tunable, fully integrated filters for the application of cognitive radio and signal classification receivers. The approach under study is the N-path filter technique which is capable of translating a baseband impedance to a reference frequency creating a tunable filter. The traditional N-path filter suffers from fundamental architectural limitations, namely : a trade-off between insertion loss and out-of-band rejection, reference clock feed- through, and jammer power handling limitations. In the first approach, the fundamental trade- off of the traditional N-path filter between insertion loss and out-of-band rejection is improved by a transmission line (T-line) N-path filter technique.
上傳時間： 2020-05-31
上傳用戶：shancjb
This book provides the essential design techniques for radio systems that operate at frequencies of 3 MHz to 100 GHz and which will be employed in the telecommunication service. We may also call these wireless systems, wireless being synonymous with radio, Telecommunications is a vibrant indus- try, particularly on the ‘‘radio side of the house.’’ The major supporter of this upsurge in radio has been the IEEE and its 802 committees. We now devote ? . an entire chapter to wireless LANs WLANs detailed in IEEE 802.11. We also now have subsections on IEEE 802.15, 802.16, 802.20 and the wireless ? . ? metropolitan area network WMAN . WiFi, WiMax,, and UWB ultra wide- . band are described where these comparatively new radio specialties are demonstrating spectacular growth.
標簽： Telecommunication Design System Radio for
上傳時間： 2020-06-01
上傳用戶：shancjb
Software Radio (SR) is one of the most important emerging technologies for the future of wireless communication services. By moving radio functionality into software, it promises to give flexible radio systems that are multi-service, multi- standard, multi-band, reconfigurable and reprogrammable by software. Today’s radios are matched to a particular class of signals that are well defined bytheircarrierfrequencies,modulationformatsandbandwidths.Aradiotransmitter today can only up convert signals with well-defined bandwidths over defined center frequencies, while, on the other side of the communication chain, a radio receiver can only down convert well-defined signal bandwidths, transmitted over specified carrier frequencies.
上傳時間： 2020-06-01
上傳用戶：shancjb
Recent advances in wireless communication technologies have had a transforma- tive impact on society and have directly contributed to several economic and social aspects of daily life. Increasingly, the untethered exchange of information between devices is becoming a prime requirement for further progress, which is placing an ever greater demand on wireless bandwidth. The ultra wideband (UWB) system marks a major milestone in this progress. Since 2002, when the FCC allowed the unlicensed use of low-power, UWB radio signals in the 3.1–10.6GHz frequency band, there has been significant synergistic advance in this technology at the cir- cuits, architectural and communication systems levels. This technology allows for devices to communicate wirelessly, while coexisting with other users by ensuring that its power density is sufficiently low so that it is perceived as noise to other users.
上傳時間： 2020-06-01
上傳用戶：shancjb
高通(Qualcomm)藍牙芯片QCC5151_硬件設計詳細指導書（官方內部培訓手冊）共52頁其內容是針對硬件設計、部分重要元器件選擇(ESD，Filter）及走線注意事項的詳細說明。2 Power management 2.1 SMPS 2.1.1 Components specification 2.1.2 Input power supply selection 2.1.3 Minimize SMPS EMI emissions 2.1.4 Internal LDOs and digital core decoupling 2.1.5 Powering external components 2.2 Charger 2.2.1 Charger connections.2.2.2 General charger operation2.2.3 Temperature measurement during charging 2.3 SYS_CTRL 3 Bluetooth radio3.1 RF PSU component choice 3.2 RF band-pass filter3.3 Layout (天線 走線的注意事項)4 Audio4.1 Audio bypass capacitors 4.2 Earphone speaker output4.3 Line/Mic input 4.4 Headphone output optimizition5 LED pads 5.1 LED driver 5.2 Digital/Button input 5.3 Analog input5.4 Disabled 6 Reset pin (Reset#)7 QSPIinterface 8 USB interfaces 8.1 USB device port8.1.1 USB connections8.1.2 Layout notes8.1.3 USB charger detection
上傳時間： 2022-01-24
上傳用戶：XuVshu
高通(Qualcomm)藍牙芯片QCC5144_硬件設計詳細指導書（官方內部培訓手冊）其內容是針對硬件設計、部分重要元器件選擇(ESD，Filter）及走線注意事項的詳細說明。2 Power management 2.1 SMPS 2.1.1 Components specification 2.1.2 Input power supply selection 92.1.3 Minimize SMPS EMI emissions 2.1.4 Internal LDOs and digital core decoupling 2.1.5 Powering external components 2.2 Charger 2.2.1 Charger connections.2.2.2 General charger operation2.2.3 Temperature measurement during charging 2.3 SYS_CTRL 3 Bluetooth radio3.1 RF PSU component choice 3.2 RF band-pass filter3.3 Layout (天線 走線的注意事項)4 Audio4.1 Audio bypass capacitors 4.2 Earphone speaker output4.3 Line/Mic input 4.4 Headphone output optimizition5 LED pads 5.1 LED driver 5.2 Digital/Button input 5.3 Analog input5.4 Disabled 6 Reset pin (Reset#)7 USB interfaces7.1 USB device port7.1.1 USB device port7.1.2 Layout notes 7.1.3 USB charger detectionA QCC5144 VFBGA example schematic and BOM B Recommended SMPS components specificationB.1 Inductor specifition B.2 Recommended inductors B.3 SMPS capacitor specifition
上傳時間： 2022-04-07
上傳用戶：默默
窄帶物聯網(NB-IoT)窄帶物聯網（Narrow Band Internet of Things, NB-IoT）成為萬物互聯網絡的一個重要分支。NB-IoT構建于蜂窩網絡，只消耗大約180kHz的帶寬，可直接部署于GSM網絡、UMTS網絡或LTE網絡，以降低部署成本、實現平滑升級。 NB-IoT是IoT領域一個新興的技術，支持低功耗設備在廣域網的蜂窩數據連接，也被叫作低功耗廣域網(LPWAN)。NB-IoT支持待機時間長、對網絡連接要求較高設備的高效連接。據說NB-IoT設備電池壽命可以提高至少10年，同時還能提供非常全面的室內蜂窩數據連接覆蓋。2017年7月13日，ofo小黃車與中國電信、華為共同宣布，三家聯合研發的NB-IoT（Narrow Band Internet of Things，窄帶物聯網）“物聯網智能鎖”全面啟動商用。 [9] 據了解，在此次三方合作中，ofo負責智能鎖設備開發，中國電信負責提供NB-IoT物聯網的商用網絡、華為負責芯片方面的服務。此前ofo已經開始使用這款物聯網智能鎖，而此次將啟動全面的商用。
標簽： NB-IOT
上傳時間： 2022-04-19
上傳用戶：
