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The six elements of drama are plot, theme, character, language, rhythm, and spectacle.


At first glance, block diagrams such as the communication system shown in [link] probably appear complex and intimidating. There are so many different blocks and so many unfamiliarnames and acronyms! Fortunately, all the blocks can be built from six simple elements:

  • Signal generators such as oscillators , which create sine and cosine waves,
  • Linear time-invariant filters , which augment or diminish the amplitude of particularfrequencies or frequency ranges in a signal,
  • Samplers , which change analog (continuous time) signals into discrete-time signals,
  • Static nonlinearities such as squarers and quantizers which can add frequency content to a signal,
  • Linear time varying systems such as mixers that shift frequencies around in useful and understandable ways, and
  • Adaptive elements , which track the desired values of parameters as they slowly change over time.

This section provides a brief overview of these six elements. In doing so, it also reviews some of the key ideas fromsignals and systems. Later chapters explore how the elementswork, how they can be modified to accomplish particular tasks within the communication system, and how they canbe combined to create a large variety of blocks such as those that appear in [link] .

The elements of a communication system have inputs and outputs; the element itself operates on its input signal tocreate its output signal. The signals that form the inputs and outputsare functions that represent the dependence of some variable of interest (such as avoltage, current, power, air pressure, temperature, etc.) on time.

The action of an element can be described by the manner in which it operates in the “time domain,” that is, how the element changes theinput waveform moment by moment into the output waveform.Another way of describing the action of an element is by how it operates in the “frequency domain,”that is, by how the frequency content of the input relates to the frequency content of the output. [link] illustrates these two complementary ways of viewing the elements. Understanding both the time domain and frequency domainbehavior is essential. Accordingly, the following sections describe theaction of the six elements in both time and frequency.

The element transforms the input signal x into the output signal y. The action of an element can be thought of in terms of its effect on the signals in time, or (via the Fourier transform) in terms of its effect on the spectra of the signals.
The element transforms the input signal x into the output signal y . The action of an element can be thought of in terms of its effect on the signals in time, or (via the Fourier transform)in terms of its effect on the spectra of the signals.

Readers who have studied signals and systems (often required in electrical engineering degrees),will recognize that the time domain representation of a signal and its frequency domain representationare related by the Fourier transform, which is briefly reviewed in the next section.

Finding the spectrum of a signal

A signal s ( t ) can often be expressed in analytical form as a function of time t , and the Fourier transform is defined as in [link] as the integral of s ( t ) e - 2 π j f t . The resulting transform S ( f ) is a function of frequency. S ( f ) is called the spectrum of the signal s ( t ) and describes the frequencies present in the signal.For example, if the time signal is created as a sum of three sinewaves, the spectrum will have spikes corresponding to each of the constituent sines.If the time signal contains only frequencies between 100 and 200 Hz, the spectrum will be zero for all frequencies outside of this range.

Questions & Answers

what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
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.
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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