Wireless penetration has witnessed explosive growth over the last two decades. Accordingly, wireless devices have become much denser per Unit area, resulting in an overcrowded usage of wireless resources. To avoid radio interferences and packet collisions, wireless stations have to exchange control messages to coordinate well. The existing wisdoms of conveying control messages could be classified into three categories: explicit, implicit, or hybrid.
標簽： Transmission Attachment Networks Wireless in
上傳時間： 2020-05-26
上傳用戶：shancjb
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 digital dilemma: Telecoms fi rms prepare for the future is an Economist Intelligence Unit (EIU) report commissioned by WIPRO. The report strives to identify the key issues that companies within the telecoms sector are facing as they attempt to reshape their businesses to compete in a more digitised world.
上傳時間： 2020-06-01
上傳用戶：shancjb
As we enter the next millennium, there are clear technological patterns. First, the electronic industry continues to scale microelectronic structures to achieve faster devices, new devices, or more per Unit area. Secondly, electrostatic charge, electrostatic discharge (ESD), electrical overstress (EOS) and electromagnetic emissions (EMI) continue to be a threat to these scaled structures. This dichotomy presents a dilemma for the scaling of semiconductor technologies and a future threat to new technologies. Technological advancements, material changes, design techniques, and simulation can fend off this growing concern – but to maintain this ever-threatening challenge, one must continue to establish research and education in this issue.
標簽： ESD-Phenomena-and-the-Reliability
上傳時間： 2020-06-05
上傳用戶：shancjb
PCB的工藝流程詳細資料說明1.開料（CUT）開料是把原始的覆銅板切割成能在生產線上制作的板子的過程 首先我們來了解幾個概念：（1）Unit：Unit是指PCB設計工程師設計的單元圖形。（2）SET：SET是指工程師為了提高生產效率、方便生產等原因，將多個Unit拼在一起成為的一個整體的圖形。也就是我們常說的拼板，它包括單元圖形、工藝邊等等。（3）PANEL：PANEL是指PCB廠家生產時，為了提高效率、方便生產等原因，將多個SET拼在一起并加上工具板邊，組成的一塊板子。
上傳時間： 2021-11-08
上傳用戶：
微型計算機的控制核心是微處理器MPU（Microprosessor Unit），實際上，人們并不嚴格區分CPU和MPU的叫法，往往統稱為CPU。通常MPU、內存和I/O接口是做在一塊印刷電路板上的
標簽： 單片機
上傳時間： 2021-12-04
上傳用戶：
目前電動汽車主要以鋰電池作為動力來源,為了提高鋰電池的使用時間和安全性,為鋰電池提供安全良好的運行環境,電池管理系統應運而生。BMS主控單元基于S32K144汽車級單片機,通過主從式網絡控制結構能夠對鋰電池的各個參數進行采集與分析。采用擴展卡爾曼濾波對電池的荷電狀態(SOC)進行估算,克服普通估算方法無法避免電池內阻誤差的缺點,通過Matlab/Simulink軟件仿真驗證可使估算誤差達到2%以內。At present,electric vehicles mainly use lithium batteries as the power source.In order to improve the running time and safety of lithium batteries,a safe and good operating environment for power batteries is provided,and a battery management system(BMS) has emerged.The BMS main control Unit is based on the S32K144 automotive-grade control chip.Through the master-slave network control structure,it can collect and analyze the various parameters of the lithium battery.The Extended Kalman Filter(EKF) is used to estimate the state of charge(SOC) of the battery,which overcomes the shortcomings of the internal estimation method that cannot overcome the internal resistance error of the battery.It can be verified by Matlab/Simulink software simulation.The estimation error is within 2%.
上傳時間： 2022-03-26
上傳用戶：XuVshu
本系統采用電動機電樞供電回路串接采樣電阻的方式來實現對小型直流有刷電動機的轉速測量。該系統主要由二階低通濾波電路,小信號放大電路、單片機測量顯示電路、開關穩壓電源電路等組成。同時自制電機測速裝置,用高頻磁環作為載體,用線圈繞制磁環,利用電磁感應原理檢測電機運行時的漏磁,將變化的磁場信號轉化為磁環上的感應電流。用信號處理單元電路將微弱電信號轉化為脈沖信號,送由單片機檢測,從而達到準確測量電機的速度的要求。In this system, the sampling resistance of armature power supply circuit is connected in series to measure the speed of small DC brush motor. The system is mainly composed of second-order low-pass filter circuit, small signal amplifier circuit, single-chip measurement and display circuit, switching regulated power supply circuit and so on. At the same time, the self-made motor speed measuring device uses high frequency magnetic ring as the carrier, coil winding magnetic ring, and electromagnetic induction principle to detect the leakage of magnetic field during the operation of the motor, which converts the changed magnetic field signal into the induced current on the magnetic ring. The weak electric signal is transformed into pulse signal by signal processing Unit circuit, which is sent to single chip computer for detection, so as to meet the requirement of accurate measurement of motor speed.
標簽： 直流電動機
上傳時間： 2022-03-26
上傳用戶：
數字示波器功能強大,使用方便,但是價格相對昂貴。本文以Ti的MSP430F5529為主控器,以Altera公司的EP2C5T144C8 FPGA器件為邏輯控制部件設計數字示波器。模擬信號經程控放大、整形電路后形成方波信號送至FPGA測頻,根據頻率值選擇采用片上及片外高速AD分段采樣。FPGA控制片外AD采樣并將數據輸入到FIFO模塊中緩存,由單片機進行頻譜分析。測試表明:簡易示波器可以實現自動選檔、多采樣率采樣、高精度測頻及頻譜分析等功能。Digital oscilloscope is powerful and easy to use, but also expensive. The research group designed a low-cost digital oscilloscope, the chip of MSP430F5529 of TI is chosen as the main controller and the device of EP2C5T144C8 of Altera company is used as the logic control Unit. Analog signal enter the programmable amplifier circuit, shaping circuit and other pre-processing circuit. The shaped rectangular wave signal is sent to FPGA for measure the frequency. According to the frequency value to select AD on-chip or off-chip high-speed AD for sampling. FPGA controls the off-chip AD sampling and buffers AD data by FIFO module. The single chip microcomputer receives the data, and do FFT for spectrum analysis. The test shows that the simple oscilloscope can realize automatic gain selection, sampling at different sampling rates, high precision frequency measurement and spectrum analysis.
上傳時間： 2022-03-27
上傳用戶：
LED 線陣顯示裝置, 分為 LED 線性旋轉顯示主機和圖文錄入器兩部分。主機用直流電機帶動由紅綠 LED 組成的線陣旋轉, 同時線陣按照時序依次切換顯示狀態, 在固定區域利用視覺暫留效果形成 16×16 點陣, 用以顯示圖文;圖文錄入器用 HMI 觸控屏作為人機交互界面, 實現圖文錄入和回放功能。主機與圖文錄入器通過無線通信方式進行信息交互,可由圖文錄入器控制主機切換不同工作任務, 以及改變線陣顯示內容。The LED linear array display device is divided into two parts:the one is the main Unit used to display content,and the other one is used to input the contents.The main Unit is driven by a DC motor to rotate the linear array composed by red and green light emitting diodes.At the same time,the 16×16 dot matrix that switching the display state according to the time sequence on the main Unit displays pictures and texts in the fixed area,by using the visual temporary effect.The HMI touch screen is used as human machine interface to realize the function that input and playback pictures and texts.The two parts of the device communicate with each other through wireless communication.The image and text input controller can control the main Unit to switch different tasks and change the content of linear array displayed.
標簽： stc12c5a60s2 單片機 led
上傳時間： 2022-03-28
上傳用戶：jiabin
