<< Chapter < Page
  Digital signal processing - dsp     Page 17 / 24
Chapter >> Page >

The remainder of the method and the class

The nested for loops discussed above are included in the code shown in Listing 15 . As suggested above, the outer loop iterates on frequency while the inner loop iterates on the values that make up the incoming samples. The code inthe inner loop computes the sum of the product of the time series and the reference cosine and sine functions.

Listing 15. The remainder of the method and the class.
//Outer loop iterates on frequency // values.for(int i=0; i<dataLen;i++){ double freq = lowF + i*delF;double real = 0.0; double imag = 0.0;double ang = 0.0; //Inner loop iterates on time-// series points. for(int j=0; j<dataLen; j++){ real += data[j]*Math.cos( 2*pi*freq*(j-zero));imag += data[j]*Math.sin(2*pi*freq*(j-zero)); }//end inner looprealOut[i]= real/dataLen; imagOut[i]= imag/dataLen; magnitude[i]= (Math.sqrt( real*real + imag*imag))/dataLen;//Calculate and return the phase // angle in degrees.if(imag == 0.0&&real == 0.0){ang = 0.0;} else{ang = Math.atan(imag/real)*180.0/pi;}if(real<0.0&&imag == 0.0){ang = 180.0;} else if(real<0.0&&imag == -0.0){ ang = -180.0;}else if(real<0.0&&imag>0.0){ ang += 180.0;}else if(real<0.0&&imag<0.0){ ang += -180.0;}angleOut[i] = ang;}//end outer loop }//end transform method}//end class ForwardRealToComplex01

Store results in output array objects

At the end of each iteration of the inner loop, code in the outer loop deposits the real, imaginary, magnitude, and phase angle results in the outputarray objects. To accomplish this, the code:

  • Computes the magnitude or amplitude as the square root of the sum of the squares of the real and imaginary parts.
  • Performs some trigonometry operations to determine the phase angle in degrees based on the values of the real and imaginary parts.

Now you know about the dft algorithm

Now you know about the DFT algorithm. You also know about some of the fundamental aspects of spectral analysis involving the sampling frequency andthe folding frequency.

Future modules will discuss other aspects of spectral analysis including:

  • Frequency resolution versus data length.
  • The relationship between the phase angle and delays in the time domain.
  • The reversible nature of the Fourier transform involving both forward and inverse Fourier transforms.

Spectral analysis using an FFT algorithm

At this point, I will present a similar spectral analysis program that uses an FFT algorithm. I will present this program with very little discussion. I amproviding it in this module for two primary purposes:

  • To allow you to experiment and appreciate the flexibility of the DFT as compared to the FFT.
  • To allow you to experiment and appreciate the speed of the FFT as compared to the DFT.

The program named Dsp030

The program named Dsp030 is very similar to Dsp028 . The major differences are:

Questions & Answers

what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
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
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
How can I make nanorobot?
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
how can I make nanorobot?
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.
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
Privacy Information Security Software Version 1.1a
Berger describes sociologists as concerned with
Mueller Reply
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get the best Algebra and trigonometry course in your pocket!

Source:  OpenStax, Digital signal processing - dsp. OpenStax CNX. Jan 06, 2016 Download for free at https://legacy.cnx.org/content/col11642/1.38
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Digital signal processing - dsp' conversation and receive update notifications?