66
The equivalent continuous vibration value or level can also be derived from the running level by
true integration or by summing over discrete samples,
i
L
being constant or nearly constant for a time
interval
i
t
as follows:
1
2
0.1
,
0
1
10
i
n
L
i
eq T
i
t
a
a
T
=
⎡
⎤
=
⎢
⎥
⎣
⎦
∑
where
1
n
i
i
T
t
=
=
∑
From a statistical distribution giving the percentages
i
p
of the total measuring time
T
, during
which the level is within an interval(e.g.
1
dB
) around a central value
Li
, the equivalent value is
given by
1
2
0.1
,
0
1
10
100%
i
n
L
i
eq T
i
p
a
a
=
⎡
⎤
=
⎢
⎥
⎣
⎦
∑
where
1
100%
n
i
i
p
=
=
∑
o
t
τ
Linear Averaging
Averaging Time
Exponential(
τ
=RC) Averaging
t
[Figure] Weighting curves for linear and exponential integration
Содержание SLA-PA201
Страница 64: ...64 Appendix 1 The Theory for calculating RMS by ISO2631 and ISO8041 ...
Страница 67: ...67 Appendix 2 Frequency Response of Filter in the Vibration Level Meter ...
Страница 75: ...75 Appendix 3 Theory of WBCombined Filter and Frequency Response ISO6954 Filter ...
Страница 79: ...79 Fig 2 Lowpass Filter with 100Hz Cutoff Fig 3 a v transition Frequency Response ...
Страница 88: ...88 Fig 12 Error between theoretical value and measured value ...
