The Internet of Things is considered to be the next big opportunity, and challenge, for the
Internet engineering community, users of technology, companies and society as a whole. It
involves connecting embedded devices such as sensors, home appliances, weather stations
and even toys to Internet Protocol (IP) based networks. The number of IP-enabled embedded
devices is increasing rapidly, and although hard to estimate, will surely outnumber the
number of personal computers (PCs) and servers in the future. With the advances made over
the past decade in microcontroller,low-power radio, battery and microelectronic technology,
the trend in the industry is for smart embedded devices (called smart objects) to become
IP-enabled, and an integral part of the latest services on the Internet. These services are no
longer cyber, just including data created by humans, but are to become very connected to the
physical world around us by including sensor data, the monitoring and control of machines,
and other kinds of physical context. We call this latest frontier of the Internet, consisting of
wireless low-power embedded devices, the Wireless Embedded Internet. Applications that
this new frontier of the Internet enable are critical to the sustainability, efficiency and safety
of society and include home and building automation, healthcare, energy efficiency, smart
grids and environmental monitoring to name just a few.
Free Space Optical Communication (FSOC) is an effective alternative technology to
meet the Next Generation Network (NGN) demands as well as highly secured (mili-
tary) communications. FSOC includes various advantages like last mile access, easy
installation, free of Electro Magnetic Interference (EMI)/Electro Magnetic Compatibil-
ity (EMC) and license free access etc. In FSOC, the optical beam propagation in the
turbulentatmosphereisseverelyaffectedbyvariousfactorssuspendedinthechannel,
geographicallocationoftheinstallationsite,terraintypeandmeteorologicalchanges.
Therefore a rigorous experimental study over a longer period becomes significant to
analyze the quality and reliability of the FSOC channel and the maximum data rate
that the system can operate since data transmission is completely season dependent.
This book is a result of the recent rapid advances in two related technologies: com-
munications and computers. Over the past few decades, communication systems
have increased in complexity to the point where system design and performance
analysis can no longer be conducted without a significant level of computer sup-
port. Many of the communication systems of fifty years ago were either power or
noise limited. A significant degrading effect in many of these systems was thermal
noise, which was modeled using the additive Gaussian noise channel.
In this book we focus on the basic signal processing that underlies current and
future ultra wideband systems. By looking at signal processing in this way we
hope this text will be useful even as UWB applications mature and change or
regulations regarding ultra wideband systems are modified. The current UWB
field is extremely dynamic, with new techniques and ideas being presented at every
communications and signal-processing conference. The basic signal-processing
techniques presented in this text though will not change for some time to come.
Thus, we have taken a somewhat theoretical approach, which we believe is longer
lasting and more useful to the reader in the long term than an up-to-the-minute
summary that is out of date as soon as it is published.
It has been said that the move from narrowband to broadband access is the second
revolution for the Internet — ‘broadband is more bandwidth than you can use’.
Once users have experienced broadband access there is no turning back. A whole
new world of applications and services becomes possible. No longer is it the ‘world-
wide wait’. The speed of response and visual quality enabled by broadband finally
allows the Internet to reach its true potential.
In this age of science and technology, the global economy has developed so much that our
lifestyles are now extremely modernized and developed. In some ways, modern society
seems to have reached the utmost state of advancement in various areas, including eco-
nomic development, science and technology pursuit, and the utilization of the given nat-
ural environment. However, it is important to consider approaches that may allow human
beings to stay longer on the Earth while enjoying fulfilling and peaceful daily lives.
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.
電子書-RTL Design Style Guide for Verilog HDL540頁A FF having a fixed input value is generated from the description in the upper portion of
Example 2-21. In this case, ’0’ is output when the reset signal is asynchronously input,
and ’1’ is output when the START signal rises. Therefore, the FF data input is fixed at
the power supply, since the typical value ’1’ is output following the rise of the START
signal.
When FF input values are fixed, the fixed inputs become untestable and the fault detection rate drops. When implementing a scan design and converting to a scan FF, the scan
may not be executed properl not be executed properly, so such descriptions , so such descriptions are not are not recommended. recommended.[1] As in the lower
part of Example 2-21, be sure to construct a synchronous type of circuit and ensure that
the clock signal is input to the clock pin of the FF.
Other than the sample shown in Example 2-21, there are situations where for certain
control signals, those that had been switched due to the conditions of an external input
will no longer need to be switched, leaving only a FF. If logic exists in a lower level and a
fixed value is input from an upper level, the input value of the FF may also end up being
fixed as the result of optimization with logic synthesis tools. In a situation like this, while
perhaps difficult to completely eliminate, the problem should be avoided as much as possible.
