/* File Dsp028.java
Copyright 2004, R.G.BaldwinRev 5/14/04
Computes and displays the magnitude of thespectral content for up to five sinusoids having
different frequencies and amplitudes.Gets input parameters from a file named
Dsp028.txt. If that file doesn't exist in thecurrent directory, the program uses a set of
default parameters.Each parameter value must be stored as characters
on a separate line in the file named Dsp028.txt.The required parameters are as follows:
Data length as type intSample number representing zero time as type int
Lower frequency bound as type double (See note)Upper frequency bound as type double
Number of spectra as type int. Max value is 5.List of sinusoid frequency values as type double.
List of sinusoid amplitude values as type double.The number of values in each of the lists must
match the value for the number of spectra.Note: All frequency values are specified as a
double representing a fractional part of thesampling frequency. For example, a value of 0.5
specifies a frequency that is half the samplingfrequency.
Here is a set of sample parameter values. Don'tallow blank lines at the end of the data in the
file.400
00.0
1.05
0.10.2
0.30.4
0.4560
7080
90100
The plotting program that is used to plot theoutput data from this program requires that the
program implement GraphIntfc01. For example,the plotting program named Graph03 can be used
to plot the data produced by this program. Whenit is used, the usage information is:
java Graph03 Dsp028A static method named transform belonging to the
class named ForwardRealToComplex01 is used toperform the actual spectral analysis. The
method named transform does not implement an FFTalgorithm. Rather, it is more general than, but
much slower than an FFT algorithm. (See theprogram named Dsp030 for the use of an FFT
algorithm.)Tested using SDK 1.4.2 under WinXP.
************************************************/import java.util.*;
import java.io.*;class Dsp028 implements GraphIntfc01{
final double pi = Math.PI;//for simplification//Begin default parameters
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 = 1.0;int numberSpectra = 5;
//Frequencies of the sinusoidsdouble[] freq = {0.1,0.2,0.3,0.4,0.5};//Amplitudes of the sinusoids
double[]amp = {60,70,80,90,100};
//End default parameters//Following arrays will contain data that is
// input to the spectral analysis process.double[] data1;double[] data2;double[] data3;double[] data4;double[] data5;//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[] magnitude1;double[] magnitude2;double[] magnitude3;double[] magnitude4;double[] magnitude5;public Dsp028(){//constructor
//Get the parameters from a file named// Dsp028.txt. Use the default parameters
// if the file doesn't exist in the current// directory.
if(new File("Dsp028.txt").exists()){getParameters();
}//end if//Note that this program always processes
// five sinusoids, even if fewer than five// were requested as the input parameter
// for numberSpectra. In that case, the// extras are processed using default values
// and simply ignored when the results are// plotted.
//Create the raw data. Note that the// argument for a sinusoid at half the
// sampling frequency would be (2*pi*x*0.5).// This would represent one half cycle or pi
// radians per sample.//First create empty array objects.
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];//Now populate the array objects
for(int n = 0;n<len;n++){
data1[n]= amp[0]*Math.cos(2*pi*n*freq[0]);
data2[n]= amp[1]*Math.cos(2*pi*n*freq[1]);
data3[n]= amp[2]*Math.cos(2*pi*n*freq[2]);
data4[n]= amp[3]*Math.cos(2*pi*n*freq[3]);
data5[n]= amp[4]*Math.cos(2*pi*n*freq[4]);
}//end for loop//Compute magnitude spectra of the raw data
// and save it in output arrays. Note that// the real, imag, and angle arrays are not
// used later, so they are discarded each// time a new spectral analysis is performed.
magnitude1 = newdouble[len];real = new double[len];imag = new double[len];angle = new double[len];ForwardRealToComplex01.transform(data1,real,
imag,angle,magnitude1,zeroTime,lowF,highF);magnitude2 = new double[len];real = new double[len];imag = new double[len];angle = new double[len];ForwardRealToComplex01.transform(data2,real,
imag,angle,magnitude2,zeroTime,lowF,highF);magnitude3 = new double[len];real = new double[len];imag = new double[len];angle = new double[len];ForwardRealToComplex01.transform(data3,real,
imag,angle,magnitude3,zeroTime,lowF,highF);magnitude4 = new double[len];real = new double[len];imag = new double[len];angle = new double[len];ForwardRealToComplex01.transform(data4,real,
imag,angle,magnitude4,zeroTime,lowF,highF);magnitude5 = new double[len];real = new double[len];imag = new double[len];angle = new double[len];ForwardRealToComplex01.transform(data5,real,
imag,angle,magnitude5,zeroTime,lowF,highF);}//end constructor
//-------------------------------------------////This method gets processing parameters from
// a file named Dsp028.txt and stores those// parameters in instance variables belonging
// to the object of type Dsp028.void getParameters(){
int cnt = 0;//Temporary holding area for strings. Allow
// space for a few blank lines at the end// of the data in the file.
String[]data = new String[20];try{
//Open an input stream.BufferedReader inData =
new BufferedReader(new FileReader("Dsp028.txt"));
//Read and save the strings from each of// the lines in the file. Be careful to
// avoid having blank lines at the end,// which may cause an ArrayIndexOutOfBounds
// exception to be thrown.while((data[cnt] =inData.readLine()) != null){
cnt++;}//end while
inData.close();}catch(IOException e){}
//Move the parameter values from the// temporary holding array into the instance
// variables, converting from characters to// numeric values in the process.
cnt = 0;len = (int)Double.parseDouble(data[cnt++]);zeroTime = (int)Double.parseDouble(
data[cnt++]);
lowF = Double.parseDouble(data[cnt++]);
highF = Double.parseDouble(data[cnt++]);
numberSpectra = (int)Double.parseDouble(data[cnt++]);for(int fCnt = 0;fCnt<numberSpectra;
fCnt++){freq[fCnt] = Double.parseDouble(data[cnt++]);}//end for loop
for(int aCnt = 0;aCnt<numberSpectra;
aCnt++){amp[aCnt] = Double.parseDouble(data[cnt++]);}//end for loop
//Print parameter values.System.out.println();
System.out.println("Data length: " + len);System.out.println(
"Sample for zero time: " + zeroTime);System.out.println(
"Lower frequency bound: " + lowF);System.out.println(
"Upper frequency bound: " + highF);System.out.println(
"Number spectra: " + numberSpectra);System.out.println("Frequencies");
for(cnt = 0;cnt<numberSpectra;cnt++){
System.out.println(freq[cnt]);
}//end for loopSystem.out.println("Amplitudes");
for(cnt = 0;cnt<numberSpectra;cnt++){
System.out.println(amp[cnt]);
}//end for loop}//end getParameters
//-------------------------------------------////The following six methods are required by the
// interface named GraphIntfc01. The plotting// program pulls the data values to be plotted
// by calling these methods.public int getNmbr(){
//Return number of functions to// process. Must not exceed 5.
return numberSpectra;}//end getNmbr
//-------------------------------------------//public double f1(double x){
int index = (int)Math.round(x);if(index<0 ||
index>magnitude1.length-1){
return 0;}else{
return magnitude1[index];
}//end else}//end function
//-------------------------------------------//public double f2(double x){
int index = (int)Math.round(x);if(index<0 ||
index>magnitude2.length-1){
return 0;}else{
return magnitude2[index];
}//end else}//end function
//-------------------------------------------//public double f3(double x){
int index = (int)Math.round(x);if(index<0 ||
index>magnitude3.length-1){
return 0;}else{
return magnitude3[index];
}//end else}//end function
//-------------------------------------------//public double f4(double x){
int index = (int)Math.round(x);if(index<0 ||
index>magnitude4.length-1){
return 0;}else{
return magnitude4[index];
}//end else}//end function
//-------------------------------------------//public double f5(double x){
int index = (int)Math.round(x);if(index<0 ||
index>magnitude5.length-1){
return 0;}else{
return magnitude5[index];
}//end else}//end function
//-------------------------------------------//}//end class Dsp028 |
