Programmer Guide/Command Reference/EVAL/zcross: Difference between revisions

Revision as of 11:58, 11 April 2011

Compute zero crossing density.

Usage

qinterp(x {type, {, sr}})

Result: The function counts the number of zero crossings z of the function x[i] = f(i). The returned result is a scalar depending on z and the argument type.

type	description	result
0	the number of zero crossing	z
1	the zero crossing density (number of zero crossings / second)	d = z / (ncol(x) * sr)
2	the average zero crossing frequenzy (in Hz)	f = d / 2
3	the average zero crossing periode length (in seconds)	t = 1 / f = 2 / d

@@ Line 7: / Line 7: @@
 :;<var>type</var>:selects the type of result; 0 <= ''type'' <= 3 (default=0)
 :;<var>sr</var>: sampling rate in Hz (default=1)
-;Result: The function counts the number of zero crossings ''nz'' of the function <code>''x''[i] = f(i)</code>. The returned result is a scalar depending on ''nz'' and the argument ''type''.
+;Result: The function counts the number of zero crossings ''z'' of the function <code>''x''[i] = f(i)</code>. The returned result is a scalar depending on ''z'' and the argument ''type''.
 :{|class="einrahmen"
-!''type'' !! result
+!''type'' !! description !! result
 |-
-|'''0''' || the number of zero crossing ''nz''
+|'''0''' || the number of zero crossing
+|''z''
 |-
-|'''1''' || the zero crossing density ''dz'' = ''nz'' / ( '''ncol'''(''x'') * ''sr'')<BR>(number of zero crossings / second)
+|'''1''' || the zero crossing density<BR>(number of zero crossings / second)
+|''d'' = ''z'' / ('''ncol'''(''x'') * ''sr'')
 |-
-|'''2''' || the average zero crossing frequenzy (in Hz) ''f'' = ''dz'' / 2
+|'''2''' || the average zero crossing frequenzy (in Hz)
+|''f'' = ''d'' / 2
 |-
-|'''3''' || the average zero crossing periode length (in seconds) ''t'' = 2 / ''dz''
+|'''3''' || the average zero crossing periode length (in seconds)
+|''t'' = 1 / ''f'' = 2 / ''d''
 |}