nullpass - counting and estimation of Zero Passes
counting and estimation (based on autocorrelation) of the number of Zero passes of a random process. NKO is the number of values of the autocorrelation function in the positive plane. X my be a matrix or a vector. If X is a Matrix, each row vector is analyzed.
This function is for didactic purposes. It demonstrates the estimation of zero crossings of a stationary random process by evaluating the autocorrelation function. The estimated number of zero crossings is estimated by SQRT(Rxx(0)ยดยด/Rxx(0)) / %pi
// Create a low pass filtered stationary process [B,A]=butter(8,0.08); x=rand(1,4000,'normal'); y=mtlb_filter(B,A,x); XY=[x;y]; [N2,N1]=nullpass(XY); disp(N2); // estimated disp(N1); // counted
akfrader , mtlb_filter ,