fg_05_04.m

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

% fg_05_04  Realizable filter power gain
M=1000; L=128; fs=[100 10];
xa=[.083 .082 .095]; ya=[-4 -1 2];
nuc=2./fs;
nu=linspace(0,.5,M);
clr=['r','g'];
sp_fig(1,8,6);
for n=1:2, 
   k=[0:L-1];
   b1=sin(2*pi*nuc(n)*(k-L))./(pi*(k-L));
   b=[b1,2*nuc(n),b1(L:-1:1)];
   dB=20*log10(max(abs(gain_f(b,1,nu)),1.e-2));
   subplot(2,1,n);
	axis([0 5 -40 5]);
	set(gca,'fontsize',16);
   line(nu*fs(n),dB,'color',clr(n)); grid;
   ylabel('Power gain (dB)');
   ht=text(2.6,-5,['{f_s}=',int2str(fs(n)),' MHz']);
   set(ht,'fontname','times','fontsize',16);
end
xlabel('Frequency {f} (MHz)');