Why I will get error:Index exceeds matrix dimensions

I don't know why modulated(200*(index-1)+1, 200*index); will cause index exceeds matrix dimension error.

I want to cut vector modulated into ten thousand components with 200 bits in each.

And it depends on random binary vector with size is num_bit(is 10000 in this case).

num_bit = 10^4;
modulated = zeros(1, 200*num_bit);  %use 200 plot to describe one symbol

    for index = 1:num_bit
        if messenge(index) == 1
            modulated(200*(index-1)+1, 200*index);
            %modulated(200*(index-1)+1, 200*index) = ones(1, 200);
        elseif messenge(index) == 0
            %modulated(200*(index-1)+1, 200*index) = zeros(1, 200);
        end
    end

Answer 1

[Guillaume]

I'm not sure what you're trying to achieve. However,

modulated = zeros(1, 200*num_bit)

crates an array with 1 rows and plenty of columns

modulated(200*(index-1)+1, 200*index)

tries to access rows 1, 201, 401, ... of the array which has only 1 row as you created it. So, of course index exceeds dimension

Note that even if the index was valid, as it is the line is pointless since you don't do anything with the value you've read.

Answer 2

[Nicola Bombace]

The error is because at line 2 you initialise your matix with just one row, and later (at line 6) you try to access an index bigger than one.

An easy fix would be changing the line 2 in modulated = zeros(200*num_bit);