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Stage three: anticipating impairments

In the third design stage, the choices are less constrained. Elements of the third stage are shown inthe lower half of the receiver schematic (the “adaptive layer” of [link] ) and include the selection of algorithms forcarrier, timing, frame synchronization, and equalizer adaptation. There are several issues to consider.

One of the primary stage three activities is algorithm selection—which performance function to use in each block.For example, should the M 6 receiver use a phase-locked loop, a Costas loop, or a decision-directed method for carrier recovery?Is a dual loop needed to provide adequate carrier tracking, or will a single loop suffice?What performance function should be used for the equalizer? Which algorithm is best for the timing recovery?Is simple correlation suitable to locate the training and marker segment?

Once the specific methods have been chosen, it is necessary to select specific variables and parameterswithin the algorithms. This is a traditional aspectof engineering design that is increasingly dominated by computer-aided design, simulation, and visualization tools.For example, error surfaces and eye diagrams can be used to compare the performance of the various algorithms in particular settings.They can be used to help determine which technique is more effective for the application at hand.

As software-aided design packages proliferate, the need to understand the computational mechanicsunderlying a particular design becomes less of a barrier. For instance, Software Receiver Design has relied exclusively on the filter design algorithms built into M atlab . But the specification of the filter (its shape,cutoff frequencies, computational complexity, and filter length) cannot be left to M atlab . The more esoteric the algorithm, the less transparent is theprocess of selecting design parameters. Thus, Software Receiver Design has devoted considerable space to the design and operation of adaptive elements.

But, even assuming that the tradeoffs associated with each of the individual components are clear, how caneverything be integrated together to succeed at a multifaceted design objective such as the M 6 receiver?

Sources of error and tradeoffs

Even when a receiver is fully operational, it may not decode every symbol precisely. There is alwaysa chance of error. Perhaps part of the error is due to a frequency mismatch, part of the error is due tonoise in the channel, part of the error is due to a nonoptimal timing offset, etc.This section (and the next) suggest a general strategy for allocating “part of” the error to each component.Then, as long as the sum of all the partial errors does not exceed the maximum allowable error, there is a goodchance that the complete receiver will work according to its specifications.

The approach is to choose a method of measuring the amount of error, for instance, the average of the squared recovery error.Each individual component can be assigned a threshold, and its parameters can be adjusted so that it does not contributemore than its share to the total error. Assuming that the accumulation of the errors from various sourcesis additive, the complete receiver will have no larger error than the concatenation of all its parts.This additivity assumption is effectively an assumption that the individual pieces of the system do not interact witheach other. If they do (or when they do), then the threshold allotments may need to be adjusted.

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
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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