<< Chapter < Page
  Digital signal processing - dsp     Page 11 / 14
Chapter >> Page >

The class named Transform

Listing 2 presents the beginning of the class named Transform . Listing 2 also presents the beginning of an instance method of that class named doIt . The doIt method computes and returns the complex transform (via output parameters) of an incoming complex series.

Listing 2. The class named Transform.
class Transform{ void doIt(double[]realIn, double[]imagIn, double scale,double[] realOut,double[] imagOut){

The method parameters

The doIt method receives five incoming parameters. The first two parameters are references to two array objects of type double containing the real and imaginary parts of the input series.

The third parameter is a scale factor that is applied to the transform output in an attempt to keep the values in a range suitable for plotting if desired.

The last two parameters are references to array objects of type double . The results of performing the transform are used to populate these two arrays. This is the mechanism by which the object returns thetransform results to the calling program. It is assumed that all of the elements in these two array objects contain values of zero upon entry to the doIt method.

Performing the transform

The body of the doIt method is presented in Listing 3 . The code in Listing 3 iterates on the input arrays, passing each complex sample contained in those two arrays to a method named correctAndRecombine .

Listing 3. Performing the transform.
for(int cnt = 0;cnt<realIn.length;cnt++){ correctAndRecombine(realIn[cnt], imagIn[cnt], cnt,realIn.length, scale,realOut, imagOut);}//end for loop }//end doIt

The transforms of the complex input samples

Each complex value in the incoming arrays represents both a complex sample and the transform of that complex sample under the assumption that the complexsample appears at the origin of the input series.

Correct for actual position and recombine

The method named correctAndRecombine corrects the transform result for each of the complex samples in the series so as to reflect the actualposition of the complex sample in the original input series.

Then the method named correctAndRecombine adds the corrected transform result into a pair of accumulators, one for the real part and one forthe imaginary part. This accomplishes the recombination of the corrected transforms of the input samples in order to produce the transform of the entireoriginal complex input series.

The correctAndRecombine method

The correctAndRecombine method is shown in Listing 4 . Listing 4 also signals the end of the Transform class.

Listing 4. The correctAndRecombine method.
void correctAndRecombine(double realSample, double imagSample,int position, int length,double scale, double[]realOut, double[]imagOut){ //Calculate the complex transform values for// each sample in the complex output series. for(int cnt = 0; cnt<length; cnt++){ double angle =(2.0*Math.PI*cnt/length)*position; //Calculate output based on real inputrealOut[cnt] +=realSample*Math.cos(angle)/scale; imagOut[cnt]+= realSample*Math.sin(angle)/scale;//Calculate output based on imag input realOut[cnt]-= imagSample*Math.sin(angle)/scale;imagOut[cnt] +=imagSample*Math.cos(angle)/scale; }//end for loop}//end correctAndRecombine }//end class transform

Questions & Answers

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
Do somebody tell me a best nano engineering book for beginners?
s. Reply
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.
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.
is Bucky paper clear?
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.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
preparation of nanomaterial
Victor 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
Got questions? Join the online conversation and get instant answers!
QuizOver.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?