Adding two time domain vectors

So I have two vectors, say A and B. They are generated by taking beats and rate as an input. This is an ECG problem. The vectors are in the form [x t], where x is magnitude and t is the time domain. If I generate 2 different frequency signals and want to add them how should I do that?

Answer 1

[Wayne King]

You just add the two vectors if they are the same length.

   x = randn(200,1);
   y = randn(200,1);
   z = x+y;

The Fourier transform is a linear operator so the Fourier transform of x+y is just the Fourier transform of x + Fourier transform of y

[Alec Climer]

They aren't the same length. The generator functions by making a template beat of 500samples, then making a vector of N*500 in length. The faster rate has more beats and therefor is a larger vector than the lower rate. The only difference is the scaling on the time vector.

Below is a solution I found, however this doesn't work well if the time steps aren't really multiples of each other...

x_comb=[];

for w=1:length(t)

ind=find(t_fet==t(w));

x_comb(w)=x_ad(w)+x_fet(ind);

end