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(The real and complex parts of the frequency spectrum were computed at 256 frequencies between zero and the sampling frequency.)

There were 256 values plotted horizontally in each separate plot. Once again, to make it easier to view the plots on the rightmost end, I plotted the valueson a grid that is 270 units wide. This leaves some blank space on the rightmost end to contain the numbers, thus preventing the numbers from being mixed in withthe plotted values. The last actual data value coincides with the rightmost tick mark on each plot.

Perform an inverse fourier transform

After modifying the complex spectrum as described above, the program performs an inverse Fourier transform on the modified complex spectrum to produce thefiltered impulse.

The filtered impulse

The filtered impulse is shown as the bottom plot in Figure 4 . As you can see, the pulse is smeared out in time relative to the input pulse in the top plot.This is the typical result of reducing the bandwidth of a pulse.

(This particular modification of the complex spectrum resulted in a filtered pulse that has the waveform of a SIN(X)/X function. A differentmodification of the complex spectrum would have resulted in a filtered pulse with a different waveform.

This example also illustrates one of the miracles of digital signal processing. Energy appears in the output before it occurs in the input.Obviously that is not possible in the real world of analog systems, but many things are possible in the digital world that are not possible in the realworld.)

Beginning of the class for Dsp037

Listing 8 shows the beginning of the class definition for the program named Dsp037.

Listing 8. Beginning of the class for Dsp037.
class Dsp037 implements GraphIntfc01{ final double pi = Math.PI;int len = 256; double[]timeDataIn = new double[len];double[] realSpect = new double[len]; double[]imagSpect = new double[len];double[] angle = new double[len];//unused double[]magnitude = new double[len];double[] timeOut = new double[len];

Listing 8 simply declares and initializes some variables that will be used later.

Beginning of the constructor

The constructor begins in Listing 9 .

Listing 9. Beginning of the constructor.
public Dsp037(){//constructor timeDataIn[32]= 90;

Listing 9 creates the raw pulse data shown in the topmost plot in Figure 4 .

When the array object referred to by timeDataIn is created, the values of all array elements are set to zero by default. Listing 9 modifies one of the elements to have a value of 90. This results in a single impulse atan index of 32.

Compute the Fourier transform

Continuing with the constructor, the code in Listing 10 uses an FFT algorithm in the method named transform (discussed earlier) to compute the Fourier transform of the impulse.

Listing 10. Compute the Fourier transform.
//Compute FFT of the time data and save it in // the output arrays.ForwardRealToComplexFFT01.transform( timeDataIn,realSpect, imagSpect,angle, magnitude);

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
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
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
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
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
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
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Digital signal processing - dsp. OpenStax CNX. Jan 06, 2016 Download for free at https://legacy.cnx.org/content/col11642/1.38
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