# 0.3 Modelling corruption  (Page 2/11)

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When the signal arrives at the receiver, it is small and must be amplified. While it is possible to build high-gainamplifiers, the noises and interferences will also be amplified along with the signal. In particular, any noise in the amplifier itself will be increased. This is often called “thermal noise” and is usually modelled as white(independent) broadband noise. Thermal noise is inherent in any electronic components and is caused by smallrandom motions of electrons, like the Brownian motion of small particles suspended in water.

Such broadband noise is another reason that a bandpass filter is applied at the front end of the receiver. Byapplying a suitable filter, the total power in the noise (compared to the total power in the signal) can often be improved. [link] shows the spectrum of the signal as a pair of triangles centered at the carrier frequency $±{f}_{c}$ with bandwidth $2B$ . The total power in the signal is the area under the triangles. The spectrum of the noiseis the flat region, and its power is the shaded area. After applying the bandpass filter, the power in the signalremains (more or less) unchanged, while the power in the noise is greatly reduced. Thus, the signal-to-noise ratio (SNR) improves.

## Narrowband noise

Noises are not always white; that is, the spectrum may not always be flat. Stray sine waves (and othersignals with narrow spectra) may also impinge on the receiver. These may be caused by errant transmitters that accidentlybroadcast in the frequency range of the signal, or they may be harmonics of a lower frequency waveas it experiences nonlinear distortion. If these narrowband disturbances occur out of band, they willautomatically be attenuated by the bandpass filter just as if they were a component of the wideband noise.However, if they occur in the frequency region of the signal, they decrease the SNR in proportion to theirpower. Judicious use of a “notch” filter (one designed to remove just the offending frequency) can be an effectivetool.

[link] shows the spectrum of the signal as the pair of triangles, along with three narrowband interferersrepresented by the three pairs of spikes. After the bandpass filter, the two pairs of out-of-band spikes are removed,but the in-band pair remains.

Applying a narrow notch filter tuned to the frequency of the interferer allows its removal,although this cannot be done without also affecting the signal somewhat.

#### Questions & Answers

what is the stm
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?
what is a peer
What is meant by 'nano scale'?
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
what is Nano technology ?
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?
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
why we need to study biomolecules, molecular biology in nanotechnology?
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
why?
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?
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
what does nano mean?
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?
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
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
How can I make nanorobot?
Lily
Do somebody tell me a best nano engineering book for beginners?
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
how can I make nanorobot?
Lily
what is fullerene does it is used to make bukky balls
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
how did you get the value of 2000N.What calculations are needed to arrive at it
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