fg_05_07.m

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

% fg_05_07  Window power spectra.
N=31; dB0=-120; beta=2*sqrt(2)*pi;
name=str2mat('Rectangular (Boxcar)','Hamming','Blackman','Kaiser');
nu=linspace(0,.5,500);
sp_fig(1,9,6);
w=[boxcar(N),hamming(N),blackman(N),kaiser(N,beta)];
clr=['r' 'b' 'g' 'c'];
for i=1:4
   H=gain_f(w(:,i),1,nu);
   dB=20*log10(max(abs(H/H(1)),-log10(-dB0/2)));
   subplot(2,2,i);
   plot(nu,dB,'color',clr(i)); grid;
   axis([0 .5 dB0 0]);
   set(gca,'fontsize',16);
   if(i==3|i==4)
      xlabel('\nu (Hz-s)');
   end
   if(i==1|i==3)
      ylabel('dB');
   end
   ht(1)=text(.21-.12*fix(1/i),-10,name(i,:));
   set(ht,'fontsize',16);
end