Larson Davis HVM200 Reference Manual

HVM200 Reference Manual Downloading Data 3-13
hold off;
title('HVM200 Data with Wk filter');
legend('x','y','z');
save(filteredsavename,'x_axis_filt','y_axis_filt','z_axis_filt','Sample_
Rate','Sample_Time');
3.3.2 Weighting Filters for Raw Data
The "isofilwk()" function comes from sample code taken from the ISO
8041 standard. You can modify it for other weighting filters using the
desired parameters from Table 3.1, “Parameters and transfer functions
of the frequency weightings (source: ISO 8041),” on page 14-3.
Use the following script and table to adjust the raw data file for hand
arm or whole body vibrations.
isofilwk() Sample Code (ISO 8041 standard)
function y = isofilwk(x, fs)
% ISOFILWK
% Filter ISO 8041 Wk
% y = isofilwk(x,fs)
% y output signal, acceleration
% x input signal, acceleration
% fs sampling frequency Hz
% bilinear transformation algorithm is used
f1 = 0.4;
f2 = 100;
f3 = 12.5;
f4 = 12.5;
Q4 = 0.63;
f5 = 2.37;
Q5 = 0.91;
f6 = 3.35;
Q6 = 0.91;
% Note that in the function “butter” the variables Ql and Q2 are
% effectively set to equal to l/sqrt(2), therefore they don't need
% to be explicitly set here.
w3 = 2*pi*f3;
w4 = 2*pi*f4;
w5 = 2*pi*f5;
w6 = 2*pi*f6;
nyq = fs/2; % Nyquist frequency

Larson Davis HVM200 Specifications

General

Brand	Larson Davis
Model	HVM200
Category	Measuring Instruments
Language	English