p(f)-of-rz.m

单极性归零(RZ)波形的功率谱

%均匀量化过程
close all
clear
b=input('请输入线性编码位数: ')
m=2^(b-1)-1;
pause
%disp('最大量化电平')   %显示量化电平
%disp(m)
pause
figure(1)
set(1,'Position',[60,60,290,350])%设置图形大小
figure(2)
set(2,'Position',[360,60,400,350])
x=(-10:0.01:10);%
y=sin(0.1*pi*x);
ym=max(y);
y11=y./ym;
y12=y11.*(2^(b-1)-1);
y1=round(y12);
a=length(y);
N=10*b;M=b;L=10;
s1=zeros(1,a*N);
for i=1:a
    c=adc(b,y1(i));
    y2=dac(b,c);
    Y(i)=y2./(2^(b-1)-1).*ym;

s=zeros(1,N);
for j=1:L
    s(j+[0:M-1]*L)=c;
end
  s1((i-1)*N+1:i*N)=s;
end


figure(1)
plot(x,y,'m')
axis([-10 10 -1 1]);
ylabel('输出电压');xlabel('输入电压');
hold on
stairs(x,Y)
text('Position',[-0.5,-1],'String','量化输出');
text('Position',[-3.5,-3.5],'String','量化输入');
title('均匀量化过程')
grid on
hold off
figure(2)
t=y-Y;
plot(x,t)
xlabel('输入电压');ylabel('误差');
title('均匀量化误差分析')
grid on

figure(3)

 plot(s1,'K') 
axis([1000 1300 0 1.2]);
title('线性编码图')
grid on

function Y=adc(b,y)
%A/D变换,实数的线性编码
if y>0
    c1=1;
else c1=0;
    y=-y;
end
if y>=2^(b-1)
    c2=ones(1,(b-1));
else for n=1:(b-1)
        r=rem(y,2);
        y=(y-r)/2;
        code(n)=r;
    end
    c2=fliplr(code);
end
Y=[c1,c2]

function y=dac(b,c)
%D/A变换,实数的线性译码
code=c(2:b);
s=0;
for i=1:(b-1);
    s=s+code(i)*2^(b-1-i);
end
a=c(1);
y=s*((-1)^(a+1));