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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

how can chip be made from sand
Eke Reply
are nano particles real
Missy Reply
yeah
Joseph
Hello, if I study Physics teacher in bachelor, can I study Nanotechnology in master?
Lale Reply
no can't
Lohitha
where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
has a lot of application modern world
Kamaluddeen
yes
narayan
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit 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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