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Description

This program performs spectral analyses on five separate time series, each 400 samples in length.

Each time series contains a pulse and the pulses are different lengths. (The lengths of the individual pulses match that shown in Figure 1 .) Each pulse consists of a truncated sinusoid. The frequency of the sinusoid for each pulseis the same.

All frequency values are specified as type double as a fraction of the sampling frequency. The frequency of all five sinusoids is 0.0625 times thesampling frequency.

The lengths of the pulses are:

  • 25 samples
  • 50 samples
  • 100 samples
  • 200 samples
  • 400 samples

If this sounds familiar, it is because the pulses are identical to those displayed in Figure 1 and discussed under Dsp031a above.

Uses a DFT algorithm

The spectral analysis process uses a DFT algorithm and computes the amplitude of the spectral energy at 400 equally spaced frequencies between zero and thefolding frequency.

(Recall from the module titled Spectrum Analysis using Java, Sampling Frequency, Folding Frequency, and the FFT Algorithm that the folding frequency is one-half the sampling frequency.)

This program computes and displays the amplitude spectrum at frequency intervals that are one-half of the frequency intervals for a typical FFTalgorithm.

Normalize the results

The results of the spectral analysis are multiplied by the reciprocal of the lengths of the individual pulses to normalize all five plots to the same peakvalue. Otherwise, the results for the short pulses would be too small to see on the plots.

Will discuss in fragments

Once again, this program is very similar to programs explained in the previous module titled Spectrum Analysis using Java, Sampling Frequency, Folding Frequency, and the FFT Algorithm . Therefore, this discussion will be very brief.

Beginning of the class named Dsp031

The code in Listing 3 declares and initializes some variables and creates the array objects that will contain the sinusoidal pulses.

In addition, the code in Listing 3 declares reference variables that will be used to refer to array objects containing results of the spectral analysisprocess that are not used in this program.

Finally, Listing 3 declares reference variables that will be used to refer to array objects containing the results plotted in Figure 2 and Figure 3 .

Given the names of the variables, the comments, and what you learned in the earlier modules, the code in Listing 3 should be self explanatory.

Listing 3. Beginning of the class named Dsp031.
class Dsp031 implements GraphIntfc01{ final double pi = Math.PI;int len = 400;//data length //Sample that represents zero time.int zeroTime = 0; //Low and high frequency limits for the// spectral analysis. double lowF = 0.0;double highF = 0.5; int numberSpectra = 5;//Frequency of the sinusoids double freq = 0.0625;//Amplitude of the sinusoids double amp = 160;//Following arrays will contain data that is // input to the spectral analysis process.double[] data1 = new double[len]; double[]data2 = new double[len];double[] data3 = new double[len]; double[]data4 = new double[len];double[] data5 = new double[len];//Following arrays receive information back // from the spectral analysis that is not used// in this program. double[]real; double[]imag; double[]angle;//Following arrays receive the magnitude // spectral information back from the spectral// analysis process. double[]mag1; double[]mag2; double[]mag3; double[]mag4; double[]mag5;

Questions & Answers

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
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
what does nano mean?
Anassong Reply
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?
Damian Reply
absolutely yes
Daniel
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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