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
When 3GPP started standardizing the IMS a few years ago, most analysts expected the number of IMS deploymentsto grow dramatically as soon the initial IMS specifications were ready (3GPP Release 5 was functionallyfrozenin the first half of 2002and completedshortly after that). While those predictions have proven to be too aggressive owing to a number of upheavals hitting the ICT (Information and Communications Technologies) sector, we are now seeing more and more commercial IMS-based service offerings in the market. At the time of writing (May 2008), there are over 30 commercial IMS networks running live traffic, addingup to over10million IMS users aroundthe world; the IMS is beingdeployedglobally. In addition, there are plenty of ongoing market activities; it is estimated that over 130 IMS contracts have been awarded to all IMS manufacturers. The number of IMS users will grow substantially as these awarded contracts are launched commercially. At the same time, the number of IMS users in presently deployed networks is steadily increasing as new services are introduced and operators running these networks migrate their non-IMS users to their IMS networks.
標簽： Multimedia Subsystem The IMS 3G IP
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
The continuing explosive growth in mobile communication is demanding more spectrally efficient radio access technologies than the prevalent second generation (2G) systems such as GSM to handle just the voice traffic. We are already witnessing high levels of mobile penetration exceeding 70% in some countries. It is anticipated that by 2010 more than half of all communications will be carried out by mobile cellular networks. On the other hand, the information revolution and changing life habits are bringing the requirement of commu- nicating on a multimedia level to the mobile environment. But the data handling capabilities and flexibility of the 2G cellular systems are limited.
上傳時間： 2020-06-01
上傳用戶：shancjb
I can remember buying my first electronic calculator. I was teaching a graduate level statistics course and I had to have a calculator with a square root function. Back in the late 1960s, that was a pretty high-end requirement for a calculator. I managed to purchase one at the “educational discount price” of $149.95! Now, I look down at my desk at an ATmega2560 that is half the size for less than a quarter of the cost and think of all the possibilities built into that piece of hardware. I am amazed by what has happened to everything from toasters to car engines. Who-da-thunk-it 40 years ago?
上傳時間： 2020-06-09
上傳用戶：shancjb
? LLC series-resonant Half-bridge: operationand significant waveforms? Simplified model (FHA approach)? 300W design example
上傳時間： 2021-11-22
上傳用戶：
This Section covers the design of power transformers used in buck-derived topologies: forward converter, bridge, half-bridge, and full-wave centertap. Flyback transformers (actually coupled inductors) are covered in a later Section. For more specialized applications, the principles discussed herein will generally apply.
上傳時間： 2021-12-16
上傳用戶：fliang
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
通過采用無橋PFC和半橋LLC諧振變換器作為數字開關電源的主變換拓撲,基于STM32系列微控制器的全數字控制PFC和DC-DC變換器,首先對數字化開關電源方案進行對比,然后闡述了200W數字開關電源整體方案,并對數字開關電源的無橋PFC和半橋LLC變換器進行系統研究。By using a bridgeless PFC and a half-bridge LLC resonant converter as the main conversion topology of the digital switching power supply,the all-digital control PFC and DC-DC converter based on the STM32 series of microcontrollers,firstly the digital switching power supply scheme is compared,and then the overall scheme of 200 W digital switching power supply is expounded, and the bridgeless PFC and half-bridge LLC converter of digital switching power supply are systematically studied.
標簽： 數字開關電源
上傳時間： 2022-04-02
上傳用戶：qingfengchizhu
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
