bshape.m

个人硕士论文的关于数字接收机调制解调方面的matlab程序

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(1:2) v(3)-v(4)* .2 v(4)*1.2]);
    set(gcf,'num','off','name',['Baseband Shaping with a Raised Cosine Filter,' blanks(10) 'BBI 2000']);
    title('Pulse Signal');   h=get(gca,'children');
    set(h(1),'color','b');set(h(2),'color',[ .9 .8 0]);
    subplot(224);n=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 Spectrum');xlabel('f/fb');zoom xon;
end;