fg_07_22.m

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

% fg_07_22  Coherent waveforms
sp_fig(1,9,6);
set(gcf,'defaultaxesfontsize',16);
set(gcf,'defaultaxesxtick',[0,.025:.05:.475,.5]);
set(gcf,'defaultaxesxticklabel','0|||||||||||.5');

randn('seed',123);
N=1.e5; Ndft=20; Nwts=63; A=sqrt(1/.04); d=3;
b=fir_weights(Nwts,3,6,.1,.3);
s=filter(b,1,randn(1,N)/.3671);
x=s+A*randn(1,N);
y=[s(N-d+1:N) s(1:N-d)]+A*randn(1,N);
%[dB,v]=power_gain(h.*w,1);
%plot(v,dB); grid on;
%return

P=pds(s,s,Ndft,'tapered',.5);
%sum(P)/Ndft
subplot(1,4,1);
pos=get(gca,'position');
pos(4)=.8;
set(gca,'position',pos);
bar2([0:Ndft/2]/Ndft,P(1:Ndft/2+1),'b');
axis([0 .5 0 35]); grid on;
xlabel('\nu (Hz-s)'); ylabel('Power density');
Title('P_{ss}(\nu)');

P=pds(x,x,Ndft,'tapered',.5);
%sum(P)/Ndft
subplot(1,4,2);
pos=get(gca,'position');
pos(4)=.8;
set(gca,'position',pos);
bar2([0:Ndft/2]/Ndft,P(1:Ndft/2+1),'r');
axis([0 .5 0 35]); grid on;
xlabel('\nu (Hz-s)');
Title('P_{xx}(\nu)');

P=pds(y,y,Ndft,'tapered',.5);
%sum(P)/Ndft
subplot(1,4,3);
pos=get(gca,'position');
pos(4)=.8;
set(gca,'position',pos);
bar2([0:Ndft/2]/Ndft,P(1:Ndft/2+1),'r');
axis([0 .5 0 35]); grid on;
xlabel('\nu (Hz-s)');
Title('P_{yy}(\nu)');

Q=pds(x,y,Ndft,'tapered',.5);
%sum(abs(Q))/Ndft
subplot(1,4,4);
pos=get(gca,'position');
pos(4)=.8;
set(gca,'position',pos);
bar2([0:Ndft/2]/Ndft,abs(Q(1:Ndft/2+1)),'b');
axis([0 .5 0 35]); grid on;
xlabel('\nu (Hz-s)');
Title('|P_{xy}(\nu)|');