5 files changed, 153 insertions, 0 deletions
diff --git a/3812/CH4/EX4.1/4_1.sce b/3812/CH4/EX4.1/4_1.sce
new file mode 100644
index 000000000..6afc7b735
--- /dev/null
+++ b/3812/CH4/EX4.1/4_1.sce
@@ -0,0 +1,66 @@
+//example 4_1
+//determine the fourier series coefficient of the signal plot its magnitude and phase spectrum
+clear;
+close;
+clc;
+N = 10;
+n = 0:0.01:N;
+Wo = 2*%pi/N;
+xn =ones(1,length(n))+sin(Wo*n)+3*cos(Wo*n)+cos(2*Wo*n+%pi/2);
+for k =0:N-2
+  C(k+1,:) = exp(-sqrt(-1)*Wo*n.*k);
+  a(k+1) = xn*C(k+1,:)'/length(n);
+  if(abs(a(k+1))<=0.1) 
+    a(k+1)=0;
+  end
+end
+a =a';
+a_conj =conj(a);
+ak = [a_conj($:-1:1),a(2:$)];
+Mag_ak = abs(ak);
+for i = 1:length(a)
+  Phase_ak(i) = atan(imag(ak(i))/(real(ak(i))+0.0001));
+end
+Phase_ak = Phase_ak'
+Phase_ak = [Phase_ak(1:$-1) -Phase_ak($:-1:1)];
+k = -(N-2):(N-2);
+//
+figure
+subplot(2,1,1)
+a = gca();
+a.y_location = "origin";
+a.x_location = "origin";
+plot2d3('gnn',k,real(ak),5)
+poly1 = a.children(1).children(1);
+poly1.thickness = 3; 
+title('Real part of(ak)')
+xlabel('                                                       k')
+subplot(2,1,2)
+a = gca();
+a.y_location = "origin";
+a.x_location = "origin";
+plot2d3('gnn',k,imag(ak),5)
+poly1 = a.children(1).children(1);
+poly1.thickness = 3; 
+title('imaginary part of(ak)')
+xlabel('                                                       k')
+//
+figure
+subplot(2,1,1)
+a = gca();
+a.y_location = "origin";
+a.x_location = "origin";
+plot2d3('gnn',k,Mag_ak,5)
+poly1 = a.children(1).children(1);
+poly1.thickness = 3; 
+title('abs(ak)')
+xlabel('                                                       k')
+subplot(2,1,2)
+a = gca();
+a.y_location = "origin";
+a.x_location = "origin";
+plot2d3('gnn',k,Phase_ak,5)
+poly1 = a.children(1).children(1);
+poly1.thickness = 3; 
+title('<(ak)')
+xlabel('                                                       k')
diff --git a/3812/CH4/EX4.12/4_12_b.sce b/3812/CH4/EX4.12/4_12_b.sce
new file mode 100644
index 000000000..84a6c32e5
--- /dev/null
+++ b/3812/CH4/EX4.12/4_12_b.sce
@@ -0,0 +1,21 @@
+//Example 4_12_b
+clc;
+clear;
+N=8;
+n=0:0.01:N;
+Wo=3*%pi/N;
+xn=1*ones(1,length(n))+1*sin(Wo*n+%pi/4);
+for k=0:N-2
+C(k+1,:)=exp(-sqrt(-1)*Wo*n.*k);
+a(k+1)=xn*C(k+1,:)'/length(n);
+if(abs(a(k+1))<=0.1)
+a(k+1)=0;
+end
+end
+a=a';
+a_conj=conj(a);
+ak=[a_conj($:-1:1),a(2:$)];
+Mag_ak=abs(ak);
+k=-(N-2):(N-2);
+plot2d3('gnn',k,Mag_ak,5)
+xtitle('abs(ak)','k','ak')
diff --git a/3812/CH4/EX4.14.a/4_14_a.sce b/3812/CH4/EX4.14.a/4_14_a.sce
new file mode 100644
index 000000000..8f810210f
--- /dev/null
+++ b/3812/CH4/EX4.14.a/4_14_a.sce
@@ -0,0 +1,22 @@
+//Example 4_14_a
+//determine the fourier series coeffient of x(n)
+clc;
+clear;
+N=6;
+n=0:0.01:N;
+Wo=2*%pi/N;
+xn=1*ones(1,length(n))+1*cos(Wo*n);
+for k=0:N-2
+C(k+1,:)=exp(-sqrt(-1)*Wo*n.*k);
+a(k+1)=xn*C(k+1,:)'/length(n);
+if(abs(a(k+1))<=0.1)
+a(k+1)=0;
+end
+end
+a=a';
+a_conj=conj(a);
+ak=[a_conj($:-1:1),a(2:$)];
+Mag_ak=abs(ak);
+k=-(N-2):(N-2);
+plot2d3('gnn',k,Mag_ak,5)
+xtitle('abs(ak)','k','ak')
diff --git a/3812/CH4/EX4.2/4_2.sce b/3812/CH4/EX4.2/4_2.sce
new file mode 100644
index 000000000..ed0048742
--- /dev/null
+++ b/3812/CH4/EX4.2/4_2.sce
@@ -0,0 +1,23 @@
+//Example 4_2
+//Finad DTFS coefficients of periodic square wave
+clc;
+clear;
+N=10;
+N1=2;
+Wo=2*%pi/N;
+xn=ones(1,length(N));
+n=-(2*N1+1):(2*N1+1);
+a(1)=(2*N1+1)/N;
+for k=1:2*N1
+a(k+1)=sin((2*%pi*k*(N1+0.5))/N)/sin(%pi*k/N);
+a(k+1)=a(k+1)/N;
+if(abs(a(k+1))<=0.1)
+a(k+1)=0;
+end
+end
+a=a';
+a_conj=conj(a);
+ak=[a_conj($:-1:1),a(2:$)];
+k=-2*N1:2*N1;
+plot2d3('gnn',k,abs(ak))
+xtitle('Magnitude spectrum','k','jakj')
diff --git a/3812/CH4/EX4.3/4_3.sce b/3812/CH4/EX4.3/4_3.sce
new file mode 100644
index 000000000..bc17d1e5e
--- /dev/null
+++ b/3812/CH4/EX4.3/4_3.sce
@@ -0,0 +1,21 @@
+//Example 4_3
+//Discrete Time Fourier Transform coefficient of Periodic Impulse Train
+clc;
+clear;
+N=5;
+N1=-3*N:3*N;
+xn=[zeros(1,N-1),1];
+x=[1 xn xn xn xn xn xn ];
+ak=1/N;
+XW=2*%pi*ak*ones(1,2*N);
+Wo=2*%pi/N;
+n=-N:N-1;
+W=Wo*n;
+figure
+subplot(2,1,1)
+plot2d3('gnn',N1,x,2);
+xtitle('Periodic Impulse Train','n','x[n]')
+subplot(2,1,2)
+plot2d3('gnn',W,XW,2);
+xtitle('DTFT of Periodic Impulse Train','w','jX(exp(jw))j')
+disp(Wo)