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The next two chapters provide more depth and detail by outlining a complete telecommunicationsystem. When the transmitted signal is passed through the air using electromagnetic waves, it must takethe form of a continuous (analog) waveform. A good way to understand such analog signals is via the Fourier transform, and this is reviewedbriefly in  [link] . The five basic elements of the receiver will be familiar to many readers, and they are presented in [link] in a form that will be directly useful when creating M atlab implementations of the various parts of the communications system. By the end of the second layer, the basic system architecture isfixed; the ordering of the blocks in the system diagram has stabilized.

The reason digital radio is so reliable is because it employs a smart receiver. Inside each digital radio receiver, there is a tiny computer: acomputer capable of sorting through the myriad of reflected and atmospherically distorted transmissions and reconstructing a solid,usable signal for the set to process.

—from http://radioworks.cbc.ca/radio/digital-radio/drri.html (2/2/03)

Telecommunications technologies using electromagnetic transmission surround us: televisionimages flicker, radios chatter, cell phones (and telephones) ring, allowing us to see and heareach other anywhere on the planet. E-mail and the Internet link us via our computers, and a large varietyof common devices such as CDs, DVDs, and hard disks augment the traditional pencil and paper storage andtransmittal of information. People have always wished tocommunicate over long distances: to speak with someone in another country, to watch a distant sporting event, to listen to musicperformed in another place or another time, to send and receive data remotely using a personal computer.In order to implement these desires, a signal (a sound wave, a signal from a TV camera, or a sequence of computer bits)needs to be encoded, stored, transmitted, received, and decoded. Why? Consider the problem of voice or music transmission.Sending sound directly is futile because sound waves dissipate very quickly in air. But if the sound is first transformedinto electromagnetic waves, then they can be beamed over great distances very efficiently. Similarly, the TV signaland computer data can be transformed into electromagnetic waves.

Electromagnetic transmission of analog waveforms

There are some experimental (physical) facts that cause transmission systems to be constructed as they are. First,for efficient wireless broadcasting of electromagnetic energy, an antenna needs to be longer than about1/10 of a wavelength of the frequency being transmitted. The antenna at the receiver should also be proportionally sized.

The wavelength λ and the frequency f of a sinusoid are inversely proportional. For an electrical signal travelling at thespeed of light c ( = 3 × 10 8 meters/second), the relationship between wavelength and frequency is

λ = c f .

For instance, if the frequency of an electromagnetic wave is f = 10 KHz, then the length of each wave is

Questions & Answers

Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
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
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
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.
Bharti
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
Daniel
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
Maciej
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
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
NANO
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
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.
Tarell
what is the actual application of fullerenes nowadays?
Damian
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.
Tarell
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.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
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.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
Sanket Reply
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Source:  OpenStax, Software receiver design. OpenStax CNX. Aug 13, 2013 Download for free at http://cnx.org/content/col11510/1.3
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