bshape.m

对ASK调制解调进行了仿真,包括程序仿真和模型仿真

function y=bshape(x,fs,fb,N,alfa,delay);
if nargin<6; delay=8; end;
if nargin<5; alfa=.5; end;
if nargin<4; N=16; end;
if nargin<3; fb=1; end;
if nargin<2; fs=16 ; end;
if nargin<1; x=pulse(randint(1,64)); end;
b=firrcos (N,fb,2*alfa*fb,fs);
y=filter(b,1,x); y=y/max(abs(y)); m=fs;
if nargout<1;
    dt=1/m; t=0:dt:(length(y)-1)*dt;
    subplot(211);plot(t,x,t,y);
    v=axis ;axis([v(2), v(3),  -v(4)*.2, v(4)*1.2]);
    set(gcf, 'num', 'off', 'name', ...
        ['Baseband Shaping with a Raised Cosine Filter' ...
        'alfa =num2str(alfa)', 'blank(10)' 'BBI 2000']);
    title ('Pulse Signal'); h=get(gca, 'children');
    set(h(1), 'color', 'b'); set (h(2), 'color',[.9 .8 0]);
    subplot(224); length(y); eyescat(y(m:n), fb,fs,delay);
    y=fft(y)/n; y=abs(y(1:fix(n/4))) *2;
    I=find(y<1e-04); y(I)=1e-04; y=20*log10(y);
    x=fft(x)/n; x=abs(x(1:fix(n/4)))*2;
    I=find(x<1e-04);x(I)=1e-04; x=20*log10(x);
    f1=m/n; f=0:f1:(length(y)-1)*f1;
    subplot(223); plot(f,x,f,y); h=get(gca,'children');
    set(h(1), 'color', 'b'); set(h(2), 'color', [.9 .8 0]);
    title('Power Spctrum'); xlabel('f/fb'); zoom xon;
end;