ZEROCROSS

ZEROCROSS - zerocrossing rate

Usage:

ZEROCROSS x sr xmin type

Inputs:

x	signal
sr	sampling rate in Hz
xmin	threshold	0 (default)
type	Frequency | Period)

Outputs:

y	number of zero crossings

Function:

In this atom the zero crossings per second are counted, i.e. the points where between the last counted point and the current point, there exists a value xprev >= xmin and the current value xcurr<= 0 or xprev <= xmin and the current value is xcurr >= 0.

So if xmin = 0 all zero crossings, i.e. changes of signs, are counted. If xmin > 0 the signal has to exceed a certain absolute value if another point is to be counted.