# Java1478-fun with java, how and why spectral analysis works  (Page 3/9)

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Some DSP processes require extremely large numbers of multiply-add operations. In order to perform DSP in real time, the equipment used to performthe arithmetic must be extremely fast. That is where the special DSP chips, (which are designed to perform multiply-add operations at an extremely high rate of speed) earn their keep.

## The net area under the curve

If you plot a time series as a curve on a graph, as shown in Figure 3 , the sum of the values that make up the time series is an estimate of the net areaunder the curve.

(Assuming that the horizontal axis represents a value of zero, the sample values above the axis contribute a positive value to the net area and thesample values below the curve contribute a negative value to the net area. In the case of Figure 3 , I attempted to come up with a set of sample values that would produce a net area of zero. In other words, the area above thehorizontal axis was intended to perfectly balance the area below the horizontal axis.)
Figure 3. Plot of values in a time series. ## A periodic example

A periodic time series is one in which a set of sample values repeats over time, provided that you record enough samples to include one or more periods. Figure 4 shows a plot of a periodic time series. You can see that the same set of values repeats as you move from left to right on the curve plotted in Figure 4 .

Figure 4. Area under a periodic curve. ## The sum of two curves

Periodic curves can often be viewed as the sum of two curves. One of the curves is the periodic component having a zero net area under the curve whenmeasured across an even number of cycles. The other component is a constant bias offset that is added to every value of the periodic curve.

Each of the solid dark blobs in Figure 4 is a sample value. The horizontal line represents a sample value of zero. (The empty circle is the sample value half way through the sampling interval. The only reason it is different isto mark the mid point.)

## The net area under the curve

What is the net area under the curve in Figure 4 ? Can you examine the curve and come up with a good estimate. As it turns out, the net area under the curvein Figure 4 is very close to zero (at least it is as close to zero as I was able to draw it) .

Now take a look at Figure 5 . What is the net area under the curve in Figure 5 ?

Figure 5. Area under a periodic curve with an offset. ## Compare Figure 5 To Figure 4

Each of these curves describes the same periodic shape (although Figure 4 has a larger peak-to-peak amplitude, meaning simply that every value in Figure 4 has been multiplied by the same scale factor) .

However, the curve in Figure 5 is riding up on a positive bias, while the curve in Figure 4 is centered about the horizontal axis. While the net area under the curve in Figure 4 is near zero, the net area under the curve in Figure 5 is a non-zero positive value.

The curve in Figure 5 can be considered to consist of the sum of two parts. One part is a straight horizontal line on the positive side of the horizontalaxis. The other part is the periodic curve from Figure 4 , added to that positive bias.

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
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
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
what is the Synthesis, properties,and applications of carbon nano chemistry
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
how did you get the value of 2000N.What calculations are needed to arrive at it
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