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The program pulseshape.m represents the “continuous-time” or analog signal by oversampling both the data sequenceand the pulse shape by a factor of M . This technique was discussed in [link] , where an “analog” sine wave sine100hzsamp.m was represented digitally at two sampling intervals, a slow digitalinterval T s and a faster rate (shorter interval) T s / M representing the underlying analog signal. The pulse shaping itself is carried out by the filter command which convolves the pulse shape with the data sequence.

str='Transmit this text string';        % message to be transmitted m=letters2pam(str); N=length(m);        % 4-level signal of length NM=10; mup=zeros(1,N*M); mup(1:M:N*M)=m;  % oversample by M ps=hamming(M);                          % blip pulse of width Mx=filter(ps,1,mup);                     % convolve pulse shape with data
pulseshape.m applying a pulse shape to a text string (download file)
The process of pulse shaping replaces each symbol of the alphabet (in this case, ±1, ±3) with an analog pulse (in this case, the short blip function shown in the top panel).
The process of pulse shaping replaces each symbol of the alphabet (in this case, ± 1 , ± 3 ) with an analog pulse (in this case, the short blip functionshown in the top panel).

Assume the sampling period is T = 0 . 1 , and then plot the spectrum of the output x . What is the bandwidth of this signal?

Again with T = 0 . 1 , plot the spectrum of the output x when the pulse shape is changed to a rectangular pulse. (Change the definition of ps in the next to last line of pulseshape.m .) What is the bandwidth of this signal?

Can you think of a pulse shape that will have a narrower bandwidth than either of the above but that will stillbe time limited by T ? Implement it by changing the definition of ps , and check to see if you are correct.

Thus the raw message, the samples, are prepared for transmission by

  • encoding into an alphabet (in this case ± 1 , ± 3 ), and then
  • pulse shaping the elements of the alphabet using p ( t ) .

The receiver must undo these two operations; it must examine the received signal and recover the elementsof the alphabet, and then decode these to reconstruct the message. Both of these tasks are made easier using correlation, which isdiscussed in the next section. The actual decoding processes used in the receiverare then discussed in "Receive Filtering: From Signals to Symbols" .


Suppose there are two signals or sequences. Are they similar, or are they different?If one is just shifted in time relative to the other, how can the time shift be determined?The approach called correlation shifts one of the sequences in time, and calculates how well they match (by multiplying pointby point and summing) at each shift. When the sum is small, they are not much alike;when the sum is large, many terms are similar. Thus, correlation is a simple form of pattern matching,which is useful in communication systems for aligning signals in time. This can be applied at the level ofsymbols when it is necessary to find appropriate sampling times, and it can be applied at the “frame” level when it is necessaryto find the start of a message (for instance, the beginning of each frame of a television signal). This section discussesvarious techniques of cross-correlation and autocorrelation, which can be viewed in either the time domain or thefrequency domain.

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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