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.
标签： Distributed Antenna Systems
上传时间： 2020-05-27
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The goal of this book is to provide a concise but lucid explanation and deriva- tion of the fundamentals of spread-spectrum communication systems. Although spread-spectrum communication is a staple topic in textbooks on digital com- munication, its treatment is usually cursory, and the subject warrants a more intensive exposition. Originally adopted in military networks as a means of ensuring secure communication when confronted with the threats of jamming and interception, spread-spectrum systems are now the core of commercial ap- plications such as mobile cellular and satellite communication.
标签： Principles Spectrum Spread of
上传时间： 2020-05-31
上传用户：shancjb
The goal of this book is to provide a concise but lucid explanation and deriva- tion of the fundamentals of spread-spectrum communication systems. Although spread-spectrum communication is a staple topic in textbooks on digital com- munication, its treatment is usually cursory, and the subject warrants a more intensive exposition. Originally adopted in military networks as a means of ensuring secure communication when confronted with the threats of jamming and interception, spread-spectrum systems are now the core of commercial ap- plications such as mobile cellular and satellite communication.
标签： Spread-Spectrum Communication Systems 1st
上传时间： 2020-06-01
上传用户：shancjb
Wireless communications, together with its applications and underlying technologies, is among today’s most active areas of technology development. The very rapid pace of im- provements in both custom and programmable integrated circuits for signal processing ap- plications has led to the justfiable view of advanced signal processing as a key enabler of the aggressively escalating capacity demands of emerging wireless systems. Consequently, there has been a tremendous and very widespread effort on the part of the research community to develop novel signal processing techniques that can fulfill this promise.
标签： Communication Wireless Systems
上传时间： 2020-06-01
上传用户：shancjb
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上传时间： 2020-06-13
上传用户：Jack599277652
推挽式变压器的设计分为AP法和KG法两种设计方法，这两种设计方法都是以几何参数进行设计，主要区别在于，KG法是AP的基础上考虑了电压调整率，即加入电压调整率参数。下面是两种方法设计流程
标签： 变压器
上传时间： 2021-12-04
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随着物联网无线通信技术的日益发展， WiFi的网络覆盖范围大，移动便捷。传输速度快，安装简单。健康安全等优势。在生活中得到了广泛应用。WiFi模块是将WiFi无线网络协议IEEE802.11.b.g.n协议栈以及TCP/IP协议栈功能集成于模块中，并将多种接口引出。传统的硬件设备嵌入WiFi模块可以直接利用WiFi联入互联网，是实现无线智能家居，WiFi远程控制等物联网用的重要组成部分。 根据WiFi模块引出的接口或集成的功能。WiFi模块也就细分为了串口WiFi模块，SDIOWiFi模块，SPI接口WiFi模块模块，AP模块,路由器WiFi模块,WiFi控制模块等。
上传时间： 2021-12-19
上传用户：shjgzh
此问题由某客户提出，应用处理器AP 与MCU 进行I2C 通信，通信会经常发生异常，需要定位原因.
上传时间： 2022-02-22
上传用户：jason_vip1
SKYLAB面向物联网市场中的智慧物流，智能交通，智慧安防，智慧能源，智能医疗，智慧建筑，智能制造，智能家居，智能零售，智慧农业，智慧楼宇等应用场景研发推出了性能强大，且支持二次开发的2.4GHz单频及2.4/5GHz双频UART串口WiFi模块，USB接口WiFi模块，AP/Router无线路由WiFi模块及远距离图传WiFi模块，高清视频传输WiFi模块及BLE/4.2/5.0低功耗蓝牙模块等嵌入式无线WiFi模块产品。
上传时间： 2022-02-23
上传用户：kent
反激式开关电源变压器设计的详细步骤85W反激变压器设计的详细步骤 1. 确定电源规格. 1).输入电压范围Vin=90—265Vac; 2).输出电压/负载电流:Vout1=42V/2A, Pout=84W 3).转换的效率=0.80 Pin=84/0.8=105W 2. 工作频率，匝比, 最低输入电压和最大占空比确定. Ｖmos*0.8>Vinmax+n(Vo+Vf)600*0.8>373+n(42+1)得n<2.5Vd*0.8>Vinmax/n+Vo400*0.8>373/n+42得n>1.34 所以n取1.6最低输入电压Vinmin=√[(Vacmin√2)* (Vacmin√2)-2Pin(T/2-tc)/Cin=(90√2*90√2-2*105*(20/2-3)/0.00015=80V取:工作频率fosc=60KHz, 最大占空比Dmax=n(Vo+Vf)/[n(Vo+Vf)+Vinmin]= 1.6(42+1)/[1.6(42+1)+80]=0.45 Ton(max)=1/f*Dmax=0.45/60000=7.5us 3. 变压器初级峰值电流的计算. Iin-avg=1/3Pin/Vinmin=1/3*105/80=0.4AΔIp1=2Iin-avg/D=2*0.4/0.45=1.78AIpk1=Pout/?/Vinmin*D+ΔIp1=84/0.8/80/0.45=2.79A 4. 变压器初级电感量的计算. 由式子Vdc=Lp*dip/dt,得: Lp= Vinmin*Ton(max)/ΔIp1 =80*0.0000075/1.78 =337uH 取Lp=337 uH 5.变压器铁芯的选择. 根据式子Aw*Ae=Pt*1000000/[2*ko*kc*fosc*Bm*j*?],其中: Pt(标称输出功率)= Pout=84W Ko(窗口的铜填充系数)=0.4 Kc(磁芯填充系数)=1(对于铁氧体), 变压器磁通密度Bm=1500Gs j(电流密度): j=4A/mm2;Aw*Ae=84*1000000/[2*0.4*1*60*103*1500Gs*4*0.80]=0.7cm4 考虑到绕线空间,选择窗口面积大的磁芯,查表: ER40/45铁氧体磁芯的有效截面积Ae=1.51cm2 ER40/45的功率容量乘积为 Ap = 3.7cm4 >0.7cm4 故选择ER40/45铁氧体磁芯. 6.变压器初级匝数 1).由Np=Vinmin*Ton/[Ae*Bm],得: Np=80*7.5*10n-6/[1.52*10n-4*0.15] =26.31 取 Np =27T 7. 变压器次级匝数的计算. Ns1(42v)=Np/n=27/1.6=16.875 取Ns1 = 17T Ns2(15v)=(15+1)* Ns1/(42+1)=6.3T 取Ns2 = 7T
上传时间： 2022-04-15
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