Spread-spectrum communication is a core area within the field of digital
communication. Originally used in military networks as countermeasures against
the threats of jamming and interception, spread-spectrum systems are now widely
used in commercial applications and are part of several wireless and mobile
communication standards. Although spread-spectrum communication is a staple
topic in textbooks on digital communication, its treatment is usually cursory. This
book is designed to provide a more intensive examination of the subject that is
suitable for graduate students and practicing engineers with a solid background
in the theory of digital communication. As the title indicates, this book stresses
principles rather than specific current or planned systems, which are described in
manyotherbooks.My goal in this bookis to providea concisebut lucidexplanation
of the fundamentals of spread-spectrum systems with an emphasis on theoretical
principles.
The advent of modern wireless devices, such as smart phones and MID 1 terminals,
has revolutionized the way people think of personal connectivity. Such devices
encompass multiple applications ranging from voice and video to high-speed data
transfer via wireless networks. The voracious appetite of twenty-first century users
for supporting more wireless applications on a single device is ever increasing.
These devices employ multiple radios and modems that cover multiple frequency
bands and multiple standards with a manifold of wireless applications often running
simultaneously.
This chapter provides extensive coverage of existing mobile wireless technologies. Much of the
emphasis is on the highly anticipated 3G cellular networks and widely deployed wireless local
area networks (LANs), as the next-generation smart phones are likely to offer at least these two
types of connectivity. Other wireless technologies that either have already been commercialized or
are undergoing active research and standardization are introduced as well. Because standardization
plays a crucial role in developing a new technology and a market, throughout the discussion
standards organizations and industry forums or consortiums of some technologies are introduced.
In addition, the last section of this chapter presents a list of standards in the wireless arena.
This book paves the path toward fourth generation (4G) mobile communica-
tion by introducing mobility in heterogeneous IP networks with both third
generation (3G) and wireless local area networks (WLANs), which is seen as
one of the central issues in the becoming 4G of telecommunications networks
and systems. This book presents a thorough overview of 3G networks and
standards and discusses interworking and handover mechanisms between
WLANs and the Universal Mobile Telecommunication System (UMTS).
Broadband powerline communication systems are continuing to gain significant
market adoption worldwide for applications ranging from IPTV delivery to the
Smart Grid. The suite of standards developed by the HomePlug Powerline
Alliance plays an important role in the widespread deployment of broadband
PLC. To date, more than 100 million HomePlug modems are deployed and these
numbers continue to rise.
n its Framework and Roadmap for Smart Grid Interoperability standards, the US
National Institute of standards and Technology declares that a twenty-first-century
clean energy economy demands a twenty-first-century electric grid. 1 The start of the
twenty-first century marked the acceleration of the Smart Grid evolution. The goals
of this evolution are broad, including the promotion of widespread and distributed
deployment of renewable energy sources, increased energy efficiency, peak power
reduction, automated demand response, improved reliability, lower energy delivery
costs, and consumer participation in energy management.
Under the Energy Independence and Security Act of 2007 (EISA), the National Institute of
standards and Technology (NIST) was assigned “primary responsibility to coordinate
development of a framework that includes protocols and model standards for information
management to achieve interoperability of Smart Grid devices and systems…” [EISA Section
1305]. 35 This responsibility comes at a time when the electric power grid and electric power
industry are undergoing the most dramatic transformation in many decades. Very significant
investments are being made by industry and the federal government to modernize the power grid.
To realize the full benefits of these investments—and the continued investments forecast for the
coming decades—there is a continued need to establish effective smart grid 36 standards and
protocols for interoperability.
One of the predominant topics in the domain of the emerging Smart Grid can be
seen in standardization. With the combination of existing protection and automa-
tion technology with upcoming ICT-based solutions, different interoperability is-
sues arise when technologies have to be combined in the infrastructure. standards
have proven to be one of the most striking solutions to actually cope with this topic.
Since 2008, this topic has gained much attention in various political and technical
agendas.
高清電子書-C++ Primer Plus, 第6版英文版 1438頁Learning C++ is an adventure of discovery, particularly because the language accommodates several programming paradigms, including object-oriented programming,
generic programming, and the traditional procedural programming.The fifth edition of
this book described the language as set forth in the ISO C++ standards, informally
known as C++99 and C++03, or, sometimes as C++99/03. (The 2003 version was
largely a technical correction to the 1999 standard and didn’t add any new features.)
Since then, C++ continues to evolve.As this book is written, the international C++
standards Committee has just approved a new version of the standard.This standard had
the informal name of C++0x while in development, and now it will be known as
C++11. Most contemporary compilers support C++99/03 quite well, and most of the
examples in this book comply with that standard. But many features of the new standard
already have appeared in some implementations, and this edition of C++ Primer Plus
explores these new features.
C++ Primer Plus discusses the basic C language and presents C++ features, making
this book self-contained. It presents C++ fundamentals and illustrates them with short,
to-the-point programs that are easy to copy and experiment with.You learn about
input/output (I/O), how to make programs perform repetitive tasks and make choices,
the many ways to handle data, and how to use functions.You learn about the many
features C++ has added to C, including the followi
隨著光伏發電系統快速發展,以及電動汽車充電樁的普及,傳統的剩余電流保護器無法滿足實際需求。介紹了一款B型剩余電流保護器,采用磁調制剩余電流互感器和零序電流互感器采集剩余電流。根據GB/T 22794—2017標準要求,可識別1 kHz及以下的正弦交流、帶和不帶直流分量的脈動直流、平滑直流等剩余電流信號。經信號調理電路將電壓信號送到單片機進行采集和判斷。通過試驗測試,該樣機在測試精度和速度上均符合國家標準的相關要求。The rapid development of photovoltaic power generation systems and the popularity of electric vehicle charging piles make the traditional residual current protective devices unable to meet the actual demand.This paper proposed a type B residual current protective device,which uses the magnetically modulated residual current transformer and the zero sequence current transformer to acquire the residual current.According to the requirements of GB/T 22794—2017,the type B residual current protective device can detect sinusoidal AC residual current of 1kHz and below 1kHz,pulsating DC residual current with and without DC component,smooth DC residual current and so on.The signal processing circuit sends the voltage signal to the MCU for acquisition and judgment.Through experimental tests,the device meets the relevant requirements of national standards in terms of test accuracy and speed.
