Before delving into the details of orthogonal frequency division multiplexing (OFDM), relevant background material must be presented first. The purpose of this chapter is to provide the necessary building blocks for the development of OFDM principles. Included in this chapter are reviews of stochastic and random process, discrete-time signals and systems, and the Discrete Fourier Transform (DFT). Tooled with the necessary mathematical foundation, we proceed with an overview of digital communication systems and OFDM communication systems. We conclude the chapter with summaries of the OFDM wireless LAN standards currently in existence and a high-level comparison of single carrier systems versus OFDM.
上传时间： 2020-05-31
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Performance analysis belongs to the domain of applied mathematics. The major domain of application in this book concerns telecommunications sys- tems and networks. We will mainly use stochastic analysis and probability theory to address problems in the performance evaluation of telecommuni- cations systems and networks. The first chapter will provide a motivation and a statement of several problems.
标签： Communications Performance Analysis Networks of
上传时间： 2020-05-31
上传用户：shancjb
Communication protocols – for short protocols – form the basis for the opera- tion of computer networks and telecommunication systems. They are behavior conventions which describe how communication systems interact with each other in computer networks. Protocols define the temporal order of the interactions and the formats of the data units exchanged. Communication protocols comprise a wide range of different functions and mechanisms, such as the sending and receiv- ing of data units, their coding/decoding, error control mechanisms, timer control, flow control, and many others.
标签： Engineering Protocol
上传时间： 2020-05-31
上传用户：shancjb
A wireless communication network can be viewed as a collection of nodes, located in some domain, which can in turn be transmitters or receivers (depending on the network considered, nodes may be mobile users, base stations in a cellular network, access points of a WiFi mesh etc.). At a given time, several nodes transmit simultaneously, each toward its own receiver. Each transmitter–receiver pair requires its own wireless link. The signal received from the link transmitter may be jammed by the signals received from the other transmitters. Even in the simplest model where the signal power radiated from a point decays in an isotropic way with Euclidean distance, the geometry of the locations of the nodes plays a key role since it determines the signal to interference and noise ratio (SINR) at each receiver and hence the possibility of establishing simultaneously this collection of links at a given bit rate. The interference seen by a receiver is the sum of the signal powers received from all transmitters, except its own transmitter.
标签： Stochastic Geometry Networks Wireless Volume and II
上传时间： 2020-06-01
上传用户：shancjb
This paper reviews key factors to practical ESD protection design for RF and analog/mixed-signal (AMS) ICs, including general challenges emerging, ESD-RFIC interactions, RF ESD design optimization and prediction, RF ESD design characterization, ESD-RFIC co-design technique, etc. Practical design examples are discussed. It means to provide a systematic and practical design flow for whole-chip ESD protection design optimization and prediction for RF/AMS ICs to ensure 1 st Si design success.
标签： ESD_protection_for_RF_and_AMS_ICs
上传时间： 2020-06-05
上传用户：shancjb
The “bottom-line” metrics of cash flow, demand, price, and return on investment are driven by a second set of financial metrics represented by value to the customer, cost, and the pace of innovation. Get them right relative to competition and impressive bottom-line results should follow. Because of their importance, we call value to the customer, variable cost, and the pace of innovation the “fundamental metrics.”
标签： Planning Product Systems Driven Value and
上传时间： 2020-06-06
上传用户：shancjb
Control systems are used to regulate an enormous variety of machines, products, and processes. They control quantities such as motion, temperature, heat flow, fluid flow, fluid pressure, tension, voltage, and current. Most concepts in control theory are based on having sensors to measure the quantity under control. In fact, control theory is often taught assuming the availability of near-perfect feedback signals. Unfortunately, such an assumption is often invalid. Physical sensors have shortcomings that can degrade a control system.
标签： Observers Control Systems in
上传时间： 2020-06-10
上传用户：shancjb
针对嵌入式产品程序更新问题,提出了一种基于IAP技术的STM32单片机在线固件升级方案,设计了STM32单片机最小系统硬件电路和USB转串口通信电路,并给出了Bootloader程序、APP程序、PC上机程序的实现流程.实验结果表明,该方案具有简单实用、稳定性高、维护成本低和设备使用效率高的特点,适用于嵌入式产品升级.For the problem of updating embedded products program,an online firmware upgrade scheme of STM32 single chip microcomputer based on IAP technology is proposed.This scheme not only elaborates the principle of IAP technology in detail but also provides the design of the minimum system hardware circuit of STM32 MCU,the design of USB for serial communication circuit,and the implementation flow of Bootloader program,APP program and PC program.The experiment results show that the scheme is simple,practical and highly stable.In addition,it can be used to actual embedded product upgrading,significantly reducing maintenance costs and improving the efficiency of equipment.
上传时间： 2022-03-25
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在全球气候变暖和石油资源短缺的形势下,推动新能源汽车的发展将成为汽车行业一种新的发展方向。在大力发展新能源电动汽车行业的同时还应兼顾电动汽车充电设施的发展,因此对电动汽车充电桩的设计与研究显得十分必要。对电动汽车直流充电桩的硬件系统进行设计,主要的硬件电路包括安全监测电路、总压采集电路、温湿度检测电路、语音电路。软件包括主要流程图和温湿度检测流程图。Under the situation of global warming and shortage of petroleum resources,promoting the development of new energy vehicles will become a new development direction for the automotive industry.While vigorously developing the new energy electric vehicle industry,we should also take into account the development of electric vehicle charging facilities.Therefore,the design and research of electric vehicle charging piles is very necessary.The hardware system of the electric vehicle DC charging pile is designed.The main hardware circuits include safety monitoring circuit,total voltage collecting circuit,temperature and humidity detecting circuit,voice circuit and CAN communication.The software includes a main flow chart and a temperature and humidity detection flow chart.
标签： 电动汽车
上传时间： 2022-04-03
上传用户：jason_vip1
基于TMS320F28335的超声波流量计硬件原理图+软件源码本文以TMS320F28335 处理器为核心，设计一种用于管道流量测量的超声波流量计。系统硬件由核心板，超声波发射和接收电路，切换电路，超声换能器，基于ADS805 的高速信号采集电路，人机交互以及电源等模块构成。采用时差法进行管道流量测量，时差测量采用SCOT 加权的广义互相关时延估计算法。本论文设计的超声波流量计具有测量速度快、准确性好、成本低等优点。关键字：C2000，超声波，流量，广义互相关算法AbstractA kind of ultrasonic flowmeter using for the pipe flow measurement is designed based onTMS320F28335 in this paper. The system hardware consists of the following parts: the core board,ultrasonic signal transmitter and receiver circuits, switch circuit, ultrasonic transducer, signalacquisition circuit based on ADS805, human-computer interaction module and power supplymodule, etc. The system use the method of time difference for pipeline flow measurement and thetime difference is calculated by the time-delay algorithm of SCOT weighted generalizedcross-correlation. The ultrasonic flowmeter has the features of high testing speed, high precisionand low cost, etc.Keywords: C2000,Ultrasonic, Flow, Generalized Cross-Correlation Algorithm
标签： tms320f28335 超声波流量计
上传时间： 2022-05-06
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