fg_07_19.m

英文书《Digital Signal Processing with Examples in MATLAB》附带的MATLAB实例

% fg_07_19      PDS of filtered Gaussian noise - changing window.
sp_fig(1,9,5.5);
set(gcf,'defaultaxesfontsize',16);

N=2^12; NH=500; y2=2; K=64;
randn('seed',12345);
x=randn(1,N);
[b,a]=ch_weights(3,8,-40,.1,.4);
H=abs(gain(b,a,NH)).^2;
y=filters(b,a,x);

subplot(1,3,1);
[p,Nsg]=pds(y,y,K,1,.95);
rectangular_power=sum(p)
bar2([0:K/2]/K,p(1:K/2+1),'r'); grid on;
line([0:NH-1]*.5/NH,H,'color','b','linewidth',1.5);
axis([0 .5 0 y2]);
xlabel('\nu (Hz-s)'); ylabel('Power density, P_y(\nu)');
title('Rectangular window');

subplot(1,3,2);
[p,Nsg]=pds(y,y,K,4,.95);
Hanning_power=sum(p)
bar2([0:K/2]/K,p(1:K/2+1),'r'); grid on;
line([0:NH-1]*.5/NH,H,'color','b','linewidth',1.5);
axis([0 .5 0 y2]);
xlabel('\nu (Hz-s)'); title('Hanning window');

subplot(1,3,3);
[p,Nsg]=pds(y,y,K,6,.95);
Blackman_power=sum(p)
bar2([0:K/2]/K,p(1:K/2+1),'r'); grid on;
line([0:NH-1]*.5/NH,H,'color','b','linewidth',1.5);
axis([0 .5 0 y2]);
xlabel('\nu (Hz-s)'); title('Blackman window');