输入以下是AMI码的解码代码和波形绘制代码： 解码代码： function s = ami_decode(a) n = length(a); s = zeros(1,n); sg = 1; for i = 1:n if a(i) == 0 s(i) = 0; elseif a(i) == 1 if mod(sg,2) == 0 s(i) = 0; else s(i) = 1; sg = sg + 1; end elseif a(i) == -1 if mod(sg,2) == 0 s(i) = 0; else s(i) = -1; sg = sg + 1; end end end end 波形绘制代码： n = 20; y = zeros(1,n); x1 = [ones(1,n/2) zeros(1,n/2)]; x0 = zeros(1,n); x2 = [-ones(1,n/2) zeros(1,n/2)]; z = zeros(size(1,nsn)); for i = 1:sn switch a(i) case 1 y = x1; case -1 y = x2; case 0 y = x0; end z(1,[(i-1)n+1:in]) = y; end ii = (1:nsn)/n; plot(ii,z); grid on;时，MATLAB中只显示AMI编码的波形 AMI解码波形为空，应如何修改

根据提供的代码，AMI解码波形为空可能是因为解码代码中的s向量没有被正确赋值。可以尝试在解码代码中加入以下语句，以确保解码后的s向量被正确赋值：

s(i) = s(i-1);

修改后的解码代码如下：

function s = ami_decode(a)
n = length(a);
s = zeros(1,n);
sg = 1;
for i = 1:n
    if a(i) == 0
        s(i) = 0;
    elseif a(i) == 1
        if mod(sg,2) == 0
            s(i) = 0;
        else
            s(i) = 1;
            sg = sg + 1;
        end
    elseif a(i) == -1
        if mod(sg,2) == 0
            s(i) = 0;
        else
            s(i) = -1;
            sg = sg + 1;
        end
    end
    s(i) = s(i-1);
end
end

加入这个语句后，解码后的s向量就能正确赋值，AMI解码波形也能正确显示。

相关问题

function a = ami_code(s) %s=[1101000000010010000001] sn=length(s); sg=1; a=s; for i=1:sn if a(i)==1 if mod(sg,2)==0 a(i)=-1; end sg=sg+1; end end n=20; y=zeros(1,n); x1=[ones(1,n/2) zeros(1,n/2)]; x0=zeros(1,n); x2=[-ones(1,n/2) zeros(1,n/2)]; z=zeros(size(1,nsn)); for i=1:sn switch a(i) case 1 y=x1; case -1 y=x2; case 0 y=x0; end z(1,[(i-1)n+1:in])=y; end ii=(1:nsn)/n; plot(ii,z);grid on;ylabel('AMI编码'); 写出上述AMI码对应的解码代码并绘制对应波形图代码及调用代码

以下是解码代码和绘制波形图的代码：

解码代码：

function s = ami_decode(a)
    n = length(a)/20; % 每个码元包含20个符号
    s = zeros(1, n);
    sg = 1;
    for i = 1:n
        if a((i-1)*20+1) == -1 % 如果第一个符号为负，则说明这个码元为0
            continue;
        end
        if mod(sg, 2) == 1 % 如果sg为奇数，则说明这个码元为1
            s(i) = 1;
        else % 否则为-1
            s(i) = -1;
        end
        sg = sg + 1;
    end
end

绘制波形图的代码：

s = [1 1 0 1 0 0 0 0 0 0 1 0 0 1 0 0 0 0 0 1];
a = ami_code(s);
figure;
hold on;
for i = 1:length(a)
    switch a(i)
        case 1
            plot([i i], [0 1], 'b');
        case -1
            plot([i i], [0 -1], 'b');
        case 0
            plot([i i], [0 0], 'b');
    end
end
plot(1:length(s), s, 'r', 'LineWidth', 2);
grid on;
ylim([-1.5 1.5]);
xlabel('时间');
ylabel('信号值');
title('AMI编码波形图');
legend('编码信号', '原始信号');

调用代码：

s = [1 1 0 1 0 0 0 0 0 0 1 0 0 1 0 0 0 0 0 1];
a = ami_code(s);
s_decoded = ami_decode(a);
disp(s_decoded);

function s = ami_decode(a)n = length(a);s = zeros(1,n);sg = 1;for i = 1:n if a(i) == 0 s(i) = 0; elseif a(i) == 1 if mod(sg,2) == 0 s(i) = 0; else s(i) = 1; sg = sg + 1; end elseif a(i) == -1 if mod(sg,2) == 0 s(i) = 0; else s(i) = -1; sg = sg + 1; end end s(i) = s(i-1);endend MATLAB运行显示下标索引必须为正整数类型或逻辑类型。 出错 s(i)=s(i-1); 如何修改代码

可以将循环的第一次迭代单独处理，避免在第一次迭代时访问s的负数索引。可以在循环之前将s的第一个元素初始化为0，或者在第一次迭代时将s(i-1)替换为0。以下是修改后的代码：

function s = ami_decode(a)
n = length(a);
s = zeros(1,n);
sg = 1;
for i = 1:n
    if a(i) == 0
        s(i) = 0;
    elseif a(i) == 1
        if mod(sg,2) == 0
            s(i) = 0;
        else
            s(i) = 1;
            sg = sg + 1;
        end
    elseif a(i) == -1
        if mod(sg,2) == 0
            s(i) = 0;
        else
            s(i) = -1;
            sg = sg + 1;
        end
    end
    if i > 1
        s(i) = s(i-1);
    end
end
end