VHDL編寫的4選一數據選擇器
entity mux41a is
port(a,b:in
std_logic;
s1,s2,s3,s4:in std_logic;
y:
Out std_logic);
end entity mux41a;
architecture one of mux41a is
signal ab:std_logic_vector(1 downto 0);
This book has grown Out of my teaching and research at the University of Surrey and Out of
my previous experiences in companies such as Philips, Ascom and Motorola. It is
primarily intended for use by students in master’s level and enhanced final-year under-
graduate courses who are specialising in communication systems and wish to understand
the principles and current practices of the wireless communication channel, including both
antenna and propagation aspects
Today’s wireless services have come a long way since the roll Out of the
conventional voice-centric cellular systems. The demand for wireless access
in voice and high rate data multi-media applications has been increasing.
New generation wireless communication systems are aimed at accommodating
this demand through better resource management and improved transmission
technologies.
The book you’re holding, physically or electronically, is the result of a very
interesting, challenging but also rewarding research project. The research was
carried Out in different contexts and cooperations but it was centered around the
following question: how can we make the RF transmitters of our modern com-
munication systems (WiFi, GSM, LTE, and so on) more flexible and more efficient
at the same time.
This book presents, in a unitary and novel perspective, some of the research work
the authors have carried Out over the last decade, along with several collaborators and
students. The roots of this book can be traced back to the design of adaptive sequence
detection algorithms for channels with parametric uncertainty. The explosion of turbo
codes and iterative decoding around the middle of the Nineties has motivated the
design of iterative (turbo and graph-based) detection algorithms.
Wireless Fidelity (Wi-Fi) networks have become mainstream over the last few years. What
started Out as cable replacement for static desktops in indoor networks has been extended
to fully mobile broadband applications involving moving vehicles, high-speed trains, and
even airplanes.
We were on the lookOut for ice.
I was in a 32 foot sailing yacht with writer and explorer Tristan Gooley, undertaking a
double-handed sail from Scotland through the Faroes up to 66 33 45.7 N and the midnight
sun. Now sailing Out of the Arctic Circle we were approaching Iceland from the north, heading
for the Denmark Straits, where ice flowed sOuth. The Admiralty Pilot warned of bergs but the
ice charts we had sailed with were over a week old. We needed an update.