<< Chapter < Page
  Digital signal processing - dsp     Page 7 / 14
Chapter >> Page >

The program named Dsp036

The program named Dsp036 replicates the behavior of the program named Dsp035 , except that it uses an FFT algorithm to perform the inverse Fourier transform instead of using a DFT algorithm as in Dsp035 .

The output from Dsp036

The output produced by running the program named Dsp036 and plotting the output using the program named Graph03 is shown in Figure 2 .

Figure 2. Forward and inverse transform of a time series using FFT algorithm.
missing image

Compare Figure 2 with Figure 1 . The two should be identical. The program named Dsp036 was designed to use an FFT algorithm for the inverse Fourier transform and to replicate the behavior of the program named Dsp035 , which uses a DFT algorithm for the inverse Fourier transform. In addition, the same plotting parameters were used for both figures.

Some code from Dsp036

I'm only going to show you one short code fragment from the program named Dsp036 . Listing 7 shows the code that calls the methods to perform the forward and inverse Fourier transforms using the FFT algorithm. A complete listing ofthe program named Dsp036 is shown in Listing 16 near the end of the module.

Listing 7. Some code from Dsp036.
//Compute FFT of the time data and save it in // the output arrays.ForwardRealToComplexFFT01.transform( timeDataIn,realSpect, imagSpect,angle, magnitude);//Compute inverse FFT of the spectral data InverseComplexToRealFFT01.inverseTransform( realSpect,imagSpect, timeOut);

The forward fourier transform

The transform method used to perform the forward Fourier transform in Listing 7 was discussed in an earlier module, so I won't discuss it further here.

The inverse fourier transform

The static inverseTransform method of the InverseComplexToRealFFT01 class was used to perform the inverse Fourier transform in Listing 7 . You can view this method in Listing 17 near the end of the module.

I'm not going to discuss this method in detail either, because it is very similar to the method named InverseComplexToReal01 discussed earlier in conjunction with Listing 4 and the listings following that one.

A couple of things to note

There are a couple of things, however, that I do want to point out.

The transform method and the inverseTransform method each call a method named complexToComplex to actually perform the Fourier transform. This method implements a classical FFT algorithm accepting complex input data and producingcomplex output data. The restriction of real-to-complex and complex-to-real is imposed in this program by the methods named transform and inverseTransform .

(The method named complexToComplex is also suitable for use if you have a need to perform complex-to-complex Fourier transforms.)

The signature of the complexToComplex method

The signature for the complexToComplex method is shown in Figure 3 .

Figure 3. The signature of the complexToComplex method.
public static void complexToComplex( int sign,int len, double real[], double imag[]){

Questions & Answers

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 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
Maciej
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
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
NANO
what is fullerene does it is used to make bukky balls
Devang Reply
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
Abhijith Reply
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
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.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
Sanket Reply
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
Good
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?

Ask