實(shí)驗(yàn)二:離散時(shí)間信號(hào)與系統(tǒng)的頻域分析

內(nèi)容一：M=256;

n=0:9;

x=0.5.^n;

k=-M:M-1;

w=(2*pi/M)*k;

X=x*(exp(-j*2*pi/M)).^(n'*k);

magX=abs(X);

phaseX=angle(X);

subplot(1,2,1);

plot(w/pi,magX);

xlabel('\omega/\pi');

subplot(1,2,2);

plot(w/pi,phaseX);

xlabel('\omega/\pi');

ylabel('\phi(\omega)');

grid;

內(nèi)容二：k=256;

num=[0.8,-0.44,0.36,0.02];

den=[1,0.7,-0.45,-0.3];

w=0:pi/k:pi;

h=freqz(num,den,w);

subplot(2,2,1);

plot(w/pi,real(h));

grid;

title('êμ2¿');

xlabel('\omega/\pi');

ylabel('·ù¶è');

subplot(2,2,2);

plot(w/pi,imag(h));

grid;

title('Dé2¿');

xlabel('\omega/\pi');

ylabel('·ù¶è');

subplot(2,2,3);

plot(w/pi,abs(h));

grid;

title('·ù¶èÆ×');

xlabel('\omega/\pi');

ylabel('·ù¶è');

subplot(2,2,4);

plot(w/pi,angle(h));

grid;

title('ÏàλÆ×');

xlabel('\omega/\pi');

ylabel('»¡¶è');