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.
上傳時間： 2020-05-31
上傳用戶：shancjb
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.
標簽： Communications Performance Analysis Networks of
上傳時間： 2020-05-31
上傳用戶：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.
標簽： Engineering Protocol
上傳時間： 2020-05-31
上傳用戶：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.
標簽： Stochastic Geometry Networks Wireless Volume and II
上傳時間： 2020-06-01
上傳用戶：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.
標簽： ESD_protection_for_RF_and_AMS_ICs
上傳時間： 2020-06-05
上傳用戶：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.”
標簽： Planning Product Systems Driven Value and
上傳時間： 2020-06-06
上傳用戶：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.
標簽： Observers Control Systems in
上傳時間： 2020-06-10
上傳用戶：shancjb
針對嵌入式產品程序更新問題,提出了一種基于IAP技術的STM32單片機在線固件升級方案,設計了STM32單片機最小系統硬件電路和USB轉串口通信電路,并給出了Bootloader程序、APP程序、PC上機程序的實現流程.實驗結果表明,該方案具有簡單實用、穩定性高、維護成本低和設備使用效率高的特點,適用于嵌入式產品升級.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.
上傳時間： 2022-03-25
上傳用戶：
在全球氣候變暖和石油資源短缺的形勢下,推動新能源汽車的發展將成為汽車行業一種新的發展方向。在大力發展新能源電動汽車行業的同時還應兼顧電動汽車充電設施的發展,因此對電動汽車充電樁的設計與研究顯得十分必要。對電動汽車直流充電樁的硬件系統進行設計,主要的硬件電路包括安全監測電路、總壓采集電路、溫濕度檢測電路、語音電路。軟件包括主要流程圖和溫濕度檢測流程圖。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.
標簽： 電動汽車
上傳時間： 2022-04-03
上傳用戶：jason_vip1
基于TMS320F28335的超聲波流量計硬件原理圖+軟件源碼本文以TMS320F28335 處理器為核心，設計一種用于管道流量測量的超聲波流量計。系統硬件由核心板，超聲波發射和接收電路，切換電路，超聲換能器，基于ADS805 的高速信號采集電路，人機交互以及電源等模塊構成。采用時差法進行管道流量測量，時差測量采用SCOT 加權的廣義互相關時延估計算法。本論文設計的超聲波流量計具有測量速度快、準確性好、成本低等優點。關鍵字：C2000，超聲波，流量，廣義互相關算法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
標簽： tms320f28335 超聲波流量計
上傳時間： 2022-05-06
上傳用戶：
