Programmer Guide/Command Reference/EVAL/zcross: Difference between revisions
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{{DISPLAYTITLE:{{SUBPAGENAME}}}} | {{DISPLAYTITLE:{{SUBPAGENAME}}}} | ||
Compute zero crossing density. | Compute zero crossing density. | ||
;Usage: | ;Usage: | ||
:<code> | :<code>zcross(<var>x</var> {<var>type</var> {, <var>sr</var> {, <var>xth</var>}}})</code> | ||
:;<var>x</var>:data vector (signal) | :;<var>x</var>:data vector (signal) | ||
:;<var>type</var>:selects the type of result; 0 | :;<var>type</var>:selects the type of result; 0 ≤ ''type'' ≤ 3 (default=0) | ||
:;<var>sr</var>: sampling rate in Hz (default=1) | :;<var>sr</var>: sampling rate in Hz (default=1) | ||
;Result: The function counts the number of zero crossings '' | :;<var>xth</var>: threshold value (default=0); if ''xth'' is a value greater than 0, fluctuations of the function in the range ''-xth'' < ''x''[i] < ''xth'' are ignored | ||
;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" | :{|class="einrahmen" | ||
!''type'' !! result | !''type'' !! description !! result | ||
|- | |- | ||
|'''0''' || the number of zero crossing '' | |'''0''' || the number of zero crossing | ||
|''z'' | |||
|- | |- | ||
|'''1''' || the zero crossing density '' | |'''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'' = '' | |'''2''' || the average zero crossing frequenzy (in Hz) | ||
|''f'' = ''d'' / 2 | |||
|- | |- | ||
|'''3''' || the average zero crossing periode length (in seconds) ''t'' = 2 / '' | |'''3''' || the average zero crossing periode length (in seconds) | ||
|''t'' = 1 / ''f'' = 2 / ''d'' | |||
|} | |} | ||
;See also: [[../f0ac|f0ac]] | |||
[[../#Functions|<function list>]] | |||
Latest revision as of 20:01, 21 April 2011
Compute zero crossing density.
- Usage
zcross(x {type {, sr {, xth}}})- x
- data vector (signal)
- type
- selects the type of result; 0 ≤ type ≤ 3 (default=0)
- sr
- sampling rate in Hz (default=1)
- xth
- threshold value (default=0); if xth is a value greater than 0, fluctuations of the function in the range -xth < x[i] < xth are ignored
- 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
- See also
- f0ac
