initial commit / add all books

1 files changed, 31 insertions, 0 deletions

diff --git a/2279/CH7/EX7.9/Ex7_9.sce b/2279/CH7/EX7.9/Ex7_9.sce
new file mode 100644
index 000000000..4f139a77f
--- /dev/null
+++ b/2279/CH7/EX7.9/Ex7_9.sce
@@ -0,0 +1,31 @@
+//x[n] = 1+sin(4*%pi/N)n+cos(10*%pi/N)n

+clear;

+close;

+clc;

+N = 21;

+n = 0:0.01:N;

+Wo = 2*%pi/N;

+xn =ones(1,length(n))+sin(2*Wo*n)+cos(5*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);

+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);

+subplot(2,1,1)

+plot2d3('gnn',k,Mag_ak,5)

+xtitle('abs(ak)','k','ak')

+subplot(2,1,2)

+plot2d3('gnn',k,Phase_ak,5) 

+xtitle('phase(ak)','k','ak')