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% Chapter 05: Example 05.08: HiRes Spectrum  % High resolution spectrum based on 100 samples of the signal x(n) figure n=0:99; x=cos(0.48*pi*n)+cos(0.52*pi*n); subplot(2,1,1);stem(n,x);title('signal x(n), 0<=n<=99');xlabel('n') set(gca, 'xlim', [-inf inf]); X=fft(x);magX=abs(X(1:1:51)); k=0:1:50;w=2*pi/100*k; subplot(2,1,2);plot(w/pi,magX, '-o');title('DTFT Magnitude');xlabel('frequency in pi units') set(gca, 'xlim', [-inf inf]);   % Spectrum based on the first 10 samples of x(n) figure n1=[0:1:9];y1=x(1:1:10); subplot(2,1,1);stem(n1,y1);title('signal x(n), 0<=n<=9');xlabel('n') set(gca, 'xlim', [-inf inf]); Y1=fft(y1);magY1=abs(Y1(1:1:6)); k1=0:1:5;w1=2*pi/10*k1; subplot(2,1,2);stem(w1/pi,magY1,'-o');title('Samples of DTFT Magnitude'); xlabel('frequency in pi units') set(gca, 'xlim', [-inf inf]);  % high density Spectrum (50 samples) based on the first 10 samples of x(n) figure n2=[0:1:49];y2=[x(1:1:10) zeros(1,40)]; subplot(2,1,1);stem(n2,y2);title('signal x(n), 0 <= n <= 9 + 40 zeros');xlabel('n') axis([0,50,-2.5,2.5]) Y2=fft(y2);magY2=abs(Y2(1:1:26)); k2=0:1:25;w2=2*pi/50*k2; subplot(2,1,2);plot(w2/pi,magY2,'-o');title('DTFT Magnitude');xlabel('frequency in pi units') set(gca, 'xlim', [-inf inf]);  % High density spectrum (100 samples) based on the first 10 samples of x(n) figure n3=[0:1:99];y3=[x(1:1:10) zeros(1,90)]; subplot(2,1,1);stem(n3,y3);title('signal x(n), 0 <= n <= 9 + 90 zeros');xlabel('n') axis([0,100,-2.5,2.5]) Y3=fft(y3);magY3=abs(Y3(1:1:51)); k3=0:1:50;w3=2*pi/100*k3; subplot(2,1,2);plot(w3/pi,magY3,'-o');title('DTFT Magnitude');xlabel('frequency in pi units') set(gca, 'xlim', [-inf inf]);