AUTOCORRELATION FOR THE CONTINUOUS TIME DEPENDENT EQUATIONS

HELLO, I AM TRYING TO PLOT AUTOCORRELATION FN FOR MY CONTINUOUS TIME DEPENDENT SYSTEM EQUATION. GENERALLY ODE45 IS USED TO SOLVE THE DIFFERENTIAL EQUATIONS.

AUTOCORRELATION FROM THE AVAILABLE LITERATURE, USED TO CALCULATE FOR SUCH CONTINUOUS SIGNAL x(t) as

   C(k) = limit T tends to infinity   ((1/T) ∫ x (t) x (t+k) dt),
  integral limit : 0 to T.

i am in doubt whether the variable x(t) is in differential form so that it can be integrated. Can any one pls help me in generating the m file for autocorrelation for the famous lorenz equations.

[Walter Roberson]

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