Mitutoyo SURFTEST SJ-410 - Rku (JIS2001, ISO1997, ANSI, VDA, Free): Kurtosis

No. 99MBB765A
23-22
23.5.9 Rku (JIS2001, ISO1997, ANSI, VDA, Free): Kurtosis
Ku represents the degree of concentration around the mean line of an amplitude
distribution curve
*1
.
∑
=
⋅=
n
i
Yi
n
Rq
Rku
1
4
4
1
1
*1: For an explanation of the amplitude distribution curve, refer to "23.5.38 ADC: Amplitude
Distribution Curve” (page 23-38).
Amplitude Distribution Curve
• For ANSI, Ku is defined over the entire evaluation length.
Large Ku
Small Ku
Triangular wave
Sine wave
Square wave
Ku = 1.79
Ku = 1.5
Ku = 1