How to plot common zero crossings of 3 different signals (3 sinusoidal signals)?

Hi, I am new to Matlab.

I am looking to plot the common zero crossings of three signals

Ex: I have 3 sine waves:

x = sin(2*pi*fo*t);

x1 = sin(t+sin(t.^2));

x2 = x+x1;

I need to find and plot the common zero crossing points in all the three signals.

Can anyone please help me out with this?

Answer 1

[Gurudatha Pai]

This may sub-optimal but definitely a start. I would find the zero crossings of each as a vector of 1's and 0's and add them. Then find the sum of them.

x_index = ZeroCrossing(x);
x1_index = ZeroCrossing(x1);
x2_index = ZeroCrossing(x2);
sum_index = x_index+x1_index+ x2_index ;
ZC_index = (sum_index == 3);

function x = ZeroCrossings(x)

    x(x>0) = 1;
    x(x<0) = 0;
    x = abs(diff(x));

end

Hope that gives you some idea! I am certain others will have better way of doing it!

I think the above code should work, but I haven't tested it!! So, please be advised!