Second-generation telecommunication systems, such as the Global System for Mobile Communications (GSM), enabled voice traffic to go wireless: the number of mobile phones exceeds the number of landline phones and the mobile phone penetration is approaching 100% in several markets. The data-handling capabilities of second-generation systems are Limited, however, and third-generation systems are needed to provide the high bit-rate services that enable high-quality images and video to be transmitted and received, and to provide access to the Web with higher data rates.
标签： Evolution WCDMA UMTS HSPA LTE for and
上传时间： 2020-06-01
上传用户：shancjb
n the first part of this book, we give an introduction to the basic applications of wireless com- munications, as well as the technical problems inherent in this communication paradigm. After a brief history of wireless, Chapter 1 describes the different types of wireless services, and works out their fundamental differences. The subsequent Section 1.3 looks at the same problem from a different angle: what data rates, ranges, etc., occur in practical systems, and especially, what combination of performance measures are demanded (e.g., what data rates need to be transmitted over short distances; what data rates are required over long distances?) Chapter 2 then describes the technical challenges of communicating without wires, putting special emphasis on fading and co-channel interference. Chapter 3 describes the most elementary problem of designing a wireless system, namely to set up a link budget in either a noise-Limited or an interference-Limited system. After studying this part of the book, the reader should have an overview of different types of wireless services, and understand the technical challenges involved in each of them. The solutions to those challenges are described in the later parts of this book.
标签： Communications Wireless Edition 2nd
上传时间： 2020-06-01
上传用户：shancjb
In the present era, low observability is one of the critical requirements in aerospace sector, especially related to defense. The stealth technology essentially relates to shaping and usage of radar absorbing materials (RAM) or radar absorbing struc- tures (RAS). The performance of such radar cross section (RCS) reduction tech- niques is Limited by the bandwidth constraints, payload requirements, and other structural issues. Moreover, with advancement of materials science, the structure geometry no longer remains key decisive factor toward stealth.
标签： Fundamentals Design Radar of EM
上传时间： 2020-06-06
上传用户：shancjb
We are in the era of ubiquitous computing in which the use and development of Radio Frequency Iden- tification (RFID) is becoming more widespread. RFID systems have three main components: readers, tags, and database. An RFID tag is composed of a small microchip, Limited logical functionality, and an antenna. Most common tags are passive and harvest energy from a nearby RFID reader. This energy is used both to energize the chip and send the answer back to the reader request. The tag provides a unique identifier (or an anonymized version of that), which allows the unequivocal identification of the tag holder (i.e. person, animal, or items).
上传时间： 2020-06-08
上传用户：shancjb
Although doing science is at the heart of discovery, the effort would have very Limited consequence in the long term without writingscience. As a social enterprise that depends on collaboration, scientific inquiry requires its practi- tioners to write on a regular basis. From time to time, some members of the scientific community have been critical of the overall quality of writing by re- searchers.
标签： Goldbort_Writing Science for
上传时间： 2020-06-09
上传用户：shancjb
This edition of Digital Image Processing is a major revision of the book. As in the 1977 and 1987 editions by Gonzalez and Wintz, and the 1992, 2002, and 2008 editions by Gonzalez and Woods, this sixth-generation edition was prepared with students and instructors in mind. The principal objectives of the book continue to be to provide an introduction to basic concepts and methodologies applicable to digital image processing, and to develop a foundation that can be used as the basis for further study and research in this field. To achieve these objectives, we focused again on material that we believe is fundamental and whose scope of application is not Limited to the solution of specialized problems. The mathematical complexity of the book remains at a level well within the grasp of college seniors and first-year graduate students who have introductory preparation in mathematical analysis, vectors, matrices, probability, statistics, linear systems, and computer programming. The book website provides tutorials to support readers needing a review of this background material
标签： Processing Digital Image
上传时间： 2021-02-20
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The PW3130 series product is a high integration solution for lithium-lion/polymer batteryprotection.PW3130 contains advanced power MOSFET, high-accuracy voltage detection circuits anddelay circuits. PW3130 is put into an ultra-small SOT23-5 package and only one external componentmakes it an ideal solution in Limited space of battery pack. PW3130 has all the protection functionsrequired in the battery application including overcharging, overdischarging, overcurrent and loadshort circuiting protection etc. The accurate overcharging detection voltage ensures safe and fullutilization charging.The low standby current drains little current from the cell while in storage. Thedevice is not only targeted for digital cellular phones, but also for any other Li-Ion and Li-Polybattery-powered information appliances requiring long-term battery life
标签： pw3130
上传时间： 2022-02-11
上传用户：fliang
研究一种智能扫地机器人。从硬件系统控制模块设计到主要技术调试进行了较详细的阐述。以STM32单片机为控制核心与电机驱动、红外线路径识别模块等相互协调应用。进行电路搭建和程序编写。实现了智能扫地机器人红外线避障和自动扫地功能,其清扫面积能达到约70%,清扫率约60%,很大程度受到自身机械机构的限制,后期将对小车的机械结构进行完善。This paper studies an intelligent sweeping robot.From the hardware system control module design to the main technical debugging are described in detail.STM32 MCU is used as the control core to coordinate with motor drive and infrared path recognition module.Conduct circuit building and programming.The functions of infrared obstacle avoidance and automatic sweeping of intelligent sweeping robot are realized.Its cleaning area can reach about 70%and the cleaning rate is about 60%.Because it is Limited by its own mechanical mechanism to a great extent,the mechanical structure of the car will be improved in the later stage.
标签： 扫地机器人
上传时间： 2022-03-26
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The information disclosed to you hereunder (the Materials ) is provided solely for the selection and use of Xilinx products. To the maximum extent permitted by applicable law: (1) Materials are made available"AS IS"and with all faults, Xilinx hereby DISCLAIMS ALL WARRANTIES AND CONDITIONS, EXPRESS, IMPLIED, OR ST ATUTORY, INCLUDING BUT NOT Limited TO WARRANTIES OF MERCHANTABILITY NON-INFRINGEMENT, OR FITNESS FOR ANY PARTICULAR PURPOSE; and (2) Xilinx shall not be liable (whether in contract or tort. includina nealigence. or under anv other theorv of liabilitv) for any loss or damage of any kind or nature related to, arising under, or in connection with, the Materials (including vour use of the Materials), including for any direct, indirect, special, incidental, or consequential loss or damage (including loss of data, profits, qoodwill, or any type of loss or damage suffered as a result of anv action brought by a third party)
上传时间： 2022-06-18
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