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.
标签： Transmission Attachment Networks Wireless in
上传时间： 2020-05-26
上传用户：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.
标签： Distributed Antenna Systems
上传时间： 2020-05-27
上传用户：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.
上传时间： 2020-06-01
上传用户：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.
标签： ESD-Phenomena-and-the-Reliability
上传时间： 2020-06-05
上传用户：shancjb
PCB的工艺流程详细资料说明1.开料（CUT）开料是把原始的覆铜板切割成能在生产线上制作的板子的过程 首先我们来了解几个概念：（1）unit：unit是指PCB设计工程师设计的单元图形。（2）SET：SET是指工程师为了提高生产效率、方便生产等原因，将多个unit拼在一起成为的一个整体的图形。也就是我们常说的拼板，它包括单元图形、工艺边等等。（3）PANEL：PANEL是指PCB厂家生产时，为了提高效率、方便生产等原因，将多个SET拼在一起并加上工具板边，组成的一块板子。
上传时间： 2021-11-08
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微型计算机的控制核心是微处理器MPU（Microprosessor unit），实际上，人们并不严格区分CPU和MPU的叫法，往往统称为CPU。通常MPU、内存和I/O接口是做在一块印刷电路板上的
标签： 单片机
上传时间： 2021-12-04
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目前电动汽车主要以锂电池作为动力来源,为了提高锂电池的使用时间和安全性,为锂电池提供安全良好的运行环境,电池管理系统应运而生。BMS主控单元基于S32K144汽车级单片机,通过主从式网络控制结构能够对锂电池的各个参数进行采集与分析。采用扩展卡尔曼滤波对电池的荷电状态(SOC)进行估算,克服普通估算方法无法避免电池内阻误差的缺点,通过Matlab/Simulink软件仿真验证可使估算误差达到2%以内。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%.
上传时间： 2022-03-26
上传用户：XuVshu
本系统采用电动机电枢供电回路串接采样电阻的方式来实现对小型直流有刷电动机的转速测量。该系统主要由二阶低通滤波电路,小信号放大电路、单片机测量显示电路、开关稳压电源电路等组成。同时自制电机测速装置,用高频磁环作为载体,用线圈绕制磁环,利用电磁感应原理检测电机运行时的漏磁,将变化的磁场信号转化为磁环上的感应电流。用信号处理单元电路将微弱电信号转化为脉冲信号,送由单片机检测,从而达到准确测量电机的速度的要求。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.
标签： 直流电动机
上传时间： 2022-03-26
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数字示波器功能强大,使用方便,但是价格相对昂贵。本文以Ti的MSP430F5529为主控器,以Altera公司的EP2C5T144C8 FPGA器件为逻辑控制部件设计数字示波器。模拟信号经程控放大、整形电路后形成方波信号送至FPGA测频,根据频率值选择采用片上及片外高速AD分段采样。FPGA控制片外AD采样并将数据输入到FIFO模块中缓存,由单片机进行频谱分析。测试表明:简易示波器可以实现自动选档、多采样率采样、高精度测频及频谱分析等功能。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.
上传时间： 2022-03-27
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LED 线阵显示装置, 分为 LED 线性旋转显示主机和图文录入器两部分。主机用直流电机带动由红绿 LED 组成的线阵旋转, 同时线阵按照时序依次切换显示状态, 在固定区域利用视觉暂留效果形成 16×16 点阵, 用以显示图文;图文录入器用 HMI 触控屏作为人机交互界面, 实现图文录入和回放功能。主机与图文录入器通过无线通信方式进行信息交互,可由图文录入器控制主机切换不同工作任务, 以及改变线阵显示内容。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.
标签： stc12c5a60s2 单片机 led
上传时间： 2022-03-28
上传用户：jiabin
