Larson Davis HVM100, Manual

Page: 17 / 174

4/11/03 Introduction 1-9
The Hand-Arm mode and the Whole body mode frequency
weighting curves are defined in ISO 8041. The W
g
fre-
quency weighting curve is defined in British Standard
6841:1987.
Band Limiting Filters
In addition to defining the frequency weightings for Hand-
Arm and Whole Body, ISO 8041 also defines a band-limit-
ing filter to be used with each of the frequency weightings.
Each band-limiting filter is a combination of a high-pass and
low-pass 2nd order Butterworth filter, 12 dB per octave
attenuation, with - 3 dB corner frequencies at the frequencies
listed in table 3 below. When a frequency weighting is
selected in the HVM100 Hand-Arm mode, or Whole Body
mode, the HVM100 automatically places both the weighting
filter and the appropriate band-limiting filter in the signal
path.
Weighting Band-Limiting Filter
W
h
6.3 to 1250 Hz
W
b,
W
c,
W
d,
W
e,
W
j,
W
k
0.4 to 100 Hz
WB, Wg 0.8 to 100 Hz