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Introduction to the subject of Information Communication and describes the necessity of a digital communication strategy for eliminating errors.

As far as a communications engineer is concerned, signals express information. Because systems manipulate signals, theyalso affect the information content. Information comes neatly packaged in both analog and digital forms. Speech, for example,is clearly an analog signal, and computer files consist of a sequence of bytes, a form of "discrete-time" signal despite thefact that the index sequences byte position, not time sample. Communication systems endeavor not to manipulate information, but to transmit it from one place toanother, so-called point-to-point communication , from one place to many others, broadcast communication , or from many to many, like a telephone conference call or a chat room. Communication systems can befundamentally analog, like radio, or digital, like computer networks.

This chapter develops a common theory that underlies how such systems work. We describe and analyze several such systems, someold like AM radio, some new like computer networks. The question as to which is better, analog or digital communication, has beenanswered, because of Claude Shannon's fundamental work on a theory of informationpublished in 1948, the development of cheap, high-performance computers, and the creation of high-bandwidth communicationsystems. The answer is to use a digital communication strategy . In most cases, you should convert all information-bearing signals into discrete-time,amplitude-quantized signals. Fundamentally digital signals, like computer files (which are a special case of symbolicsignals), are in the proper form. Because of the Sampling Theorem, we know how to convert analog signals into digitalones. Shannon showed that once in this form, a properly engineered system can communicate digital informationwith no error despite the fact that the communication channel thrusts noise onto all transmissions . This startling result has no counterpart in analog systems; AM radio willremain noisy. The convergence of these theoretical and engineering results on communications systems has had importantconsequences in other arenas. The audio compact disc (CD) and the digital videodisk (DVD) are now considered digitalcommunications systems, with communication design considerations used throughout.

Go back to the fundamental model of communication . Communications design begins with two fundamentalconsiderations.

  1. What is the nature of the information source, and to what extent can the receiver tolerate errors in the receivedinformation?
  2. What are the channel's characteristics and how do they affect the transmitted signal?
In short, what are we going to send and how are we going to sendit? Interestingly, digital as well as analog transmission are accomplished using analog signals, like voltages in Ethernet (anexample of wireline communications) and electromagnetic radiation ( wireless ) in cellular telephone.

Questions & Answers

Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
Answers please
Nikki Reply

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Source:  OpenStax, Fundamentals of electrical engineering i. OpenStax CNX. Aug 06, 2008 Download for free at http://legacy.cnx.org/content/col10040/1.9
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