Scilab Function
Last update : 1/11/2005

nullpass - counting and estimation of Zero Passes

Calling Sequence

[N2,N1] = nullpass(x,NKO)

Parameters

Description

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

Examples

// 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

See Also

akfrader ,   mtlb_filter ,  

Authors

Dr. Andreas Geissler geisslea@web.de

Bibliography

Papoulis, "Signal Analysis"

Used Function

akfrader