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 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.
標簽： Principles Spectrum Spread of
上傳時間： 2020-05-31
上傳用戶：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.
標簽： Spread-Spectrum Communication Systems 1st
上傳時間： 2020-06-01
上傳用戶：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.
標簽： Communication Wireless Systems
上傳時間： 2020-06-01
上傳用戶：shancjb
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上傳時間： 2020-06-13
上傳用戶：Jack599277652
推挽式變壓器的設計分為AP法和KG法兩種設計方法，這兩種設計方法都是以幾何參數進行設計，主要區別在于，KG法是AP的基礎上考慮了電壓調整率，即加入電壓調整率參數。下面是兩種方法設計流程
標簽： 變壓器
上傳時間： 2021-12-04
上傳用戶：
隨著物聯網無線通信技術的日益發展， WiFi的網絡覆蓋范圍大，移動便捷。傳輸速度快，安裝簡單。健康安全等優勢。在生活中得到了廣泛應用。WiFi模塊是將WiFi無線網絡協議IEEE802.11.b.g.n協議棧以及TCP/IP協議棧功能集成于模塊中，并將多種接口引出。傳統的硬件設備嵌入WiFi模塊可以直接利用WiFi聯入互聯網，是實現無線智能家居，WiFi遠程控制等物聯網用的重要組成部分。 根據WiFi模塊引出的接口或集成的功能。WiFi模塊也就細分為了串口WiFi模塊，SDIOWiFi模塊，SPI接口WiFi模塊模塊，AP模塊,路由器WiFi模塊,WiFi控制模塊等。
上傳時間： 2021-12-19
上傳用戶：shjgzh
此問題由某客戶提出，應用處理器AP 與MCU 進行I2C 通信，通信會經常發生異常，需要定位原因.
上傳時間： 2022-02-22
上傳用戶：jason_vip1
SKYLAB面向物聯網市場中的智慧物流，智能交通，智慧安防，智慧能源，智能醫療，智慧建筑，智能制造，智能家居，智能零售，智慧農業，智慧樓宇等應用場景研發推出了性能強大，且支持二次開發的2.4GHz單頻及2.4/5GHz雙頻UART串口WiFi模塊，USB接口WiFi模塊，AP/Router無線路由WiFi模塊及遠距離圖傳WiFi模塊，高清視頻傳輸WiFi模塊及BLE/4.2/5.0低功耗藍牙模塊等嵌入式無線WiFi模塊產品。
上傳時間： 2022-02-23
上傳用戶：kent
反激式開關電源變壓器設計的詳細步驟85W反激變壓器設計的詳細步驟 1. 確定電源規格. 1).輸入電壓范圍Vin=90—265Vac; 2).輸出電壓/負載電流:Vout1=42V/2A, Pout=84W 3).轉換的效率=0.80 Pin=84/0.8=105W 2. 工作頻率，匝比, 最低輸入電壓和最大占空比確定. 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最低輸入電壓Vinmin=√[(Vacmin√2)* (Vacmin√2)-2Pin(T/2-tc)/Cin=(90√2*90√2-2*105*(20/2-3)/0.00015=80V取:工作頻率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. 變壓器初級峰值電流的計算. 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. 變壓器初級電感量的計算. 由式子Vdc=Lp*dip/dt,得: Lp= Vinmin*Ton(max)/ΔIp1 =80*0.0000075/1.78 =337uH 取Lp=337 uH 5.變壓器鐵芯的選擇. 根據式子Aw*Ae=Pt*1000000/[2*ko*kc*fosc*Bm*j*?],其中: Pt(標稱輸出功率)= Pout=84W Ko(窗口的銅填充系數)=0.4 Kc(磁芯填充系數)=1(對于鐵氧體), 變壓器磁通密度Bm=1500Gs j(電流密度): j=4A/mm2;Aw*Ae=84*1000000/[2*0.4*1*60*103*1500Gs*4*0.80]=0.7cm4 考慮到繞線空間,選擇窗口面積大的磁芯,查表: ER40/45鐵氧體磁芯的有效截面積Ae=1.51cm2 ER40/45的功率容量乘積為 Ap = 3.7cm4 >0.7cm4 故選擇ER40/45鐵氧體磁芯. 6.變壓器初級匝數 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. 變壓器次級匝數的計算. Ns1(42v)=Np/n=27/1.6=16.875 取Ns1 = 17T Ns2(15v)=(15+1)* Ns1/(42+1)=6.3T 取Ns2 = 7T
上傳時間： 2022-04-15
上傳用戶：
