c5_3_1.m

dsp入门与实践一书的源代码

clear all;				
clf;
N=256;                                 	
N1=10;					
N2=300;					
f=64;                                 	
n=2;                                    
da=1.5.^0.03;				
adot=16.9348;				

dt=1/1024;                              
sample=1/dt;				
randn('state',sum(100*clock));          
dis=2*rand(1,N);
dis=dis-mean(dis);			
dis=n*dis;				
Pdis=0;					
for i=1:N;
    Pdis=Pdis+dis(i)*dis(i);
end
Pdis=Pdis/N;
SNR=10*log10(0.5/Pdis)
for k=1:N;     				
   w(k)=1*sin(2*pi*f*k*dt)+1*dis(k); 
end
for i=N1:N2;
   c=cwt(w,da.^i,'morl');               
   s(i)=0;				
   for k=1:N;
      s(i)=s(i)+c(k)*c(k);
   end
end
figure(1);										
plot(s);
xlabel('尺度等级i');
ylabel('平方累加后的小波系数');
title('2倍噪声情况下系数累加后的波形图');
smax=max(s(N1:N2));
sdot=0;
for i=N1:N2;                                 		
   if s(i)==smax;
       sdot=i;
   end
end
freq=sample/(da.^(sdot+adot));             		
precision=1000*(freq-f)/f ;				
disp(sdot);disp(freq);disp(precision);