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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

Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
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
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
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
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
hi
Loga
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
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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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