To verify the filters in NeVib (digital filter in the time domain, which simulate analog filters), a test project was created (VerificationProject ISO8041), which contains the
sawtooth signals proposed in ISO8041.
See also:
Signals in the ISO8041 test project
Measurements in the ISO8041 test project
To load this project, please click in the menu: File - Open existing project
Select the project directory "VerificationProject ISO8041" and click "Open".
In the project directory select "VerificationProject ISO8041.xml" and click "Open".
The project will be loaded and displayed:
ISO8041 supposes sawtooth signals for verifying.
channel |
Number of tone pulses per repetition period |
1 |
1 |
2 |
2 |
3 |
4 |
4 |
8 |
5 |
16 |
6 |
Continuous signal |
The breaks at the beginning, angular frequencies, duration of repetition period, overall duration are depending on the area of application (hand-arm, whole body, low frequency whole body) according to ISO8041.
The amplitude of the signals is 100 m/s².
Measurement No. |
Comment of the measurement |
Filter |
Sample rate |
Remark |
1 |
ISO8041 Wh 10 kHz (*100) |
Wh |
10000 Hz |
NeVib default sample rate for hand-arm-vibrations |
2 |
ISO8041 Wh 5120 Hz (*100) |
Wh |
5120 Hz |
Some acquisition devices support only this sample rate |
3 |
ISO8041 Wh 18432 Hz (*100) |
Wh |
18432 Hz |
Some acquisition devices support only this sample rate |
4 |
ISO8041 Wb (*100) |
Wb |
1000 Hz |
NeVib default sample rate for whole body vibrations |
5 |
ISO8041 Wc (*100) |
Wc |
1000 Hz |
NeVib default sample rate for whole body vibrations
|
6 |
ISO8041 Wd (*100) |
Wd |
1000 Hz |
NeVib default sample rate for whole body vibrations. Display in NeVib is (because of Wd, ISO2631-1, EU directive 2002_44) weighted with a factor of 1.4 |
7 |
ISO8041 We (*100) |
We |
1000 Hz |
NeVib default sample rate for whole body vibrations |
8 |
ISO8041 Wf (*100) |
Wf |
50Hz |
NeVib default sample rate for low frequency whole body vibrations (Kinetosis) |
9 |
ISO8041 Wj (*100) |
Wj |
1000 Hz |
NeVib default sample rate for whole body vibrations |
10 |
ISO8041 Wk (*100) |
Wk |
1000 Hz |
NeVib default sample rate for whole body vibrations |
11 |
ISO8041 Wm (*100) |
Wm |
1000 Hz |
NeVib default sample rate for whole body vibrations |
An example of the verification of the weighting filter is presented here .
You can download the complete verification as EXCEL worksheet: Vergleich Filter NeVib mit ISO8041.xls
click and activate the measurement wanted. I.e. No. 8, "ISO8041 Wf (*100)"
click on button "Analysis" on the bottom
Double click on a graphic. This graphic is displayed in a new window.
Here you can pick up the signals in more detail by zooming and take cursor measurements.
Please note, that the channels have partly identical signals and the lines of the graphic displays are therefore partly above each other
Click on "show results"
Explanations:
"Messpunkt 1" (upper table) belongs to the channels 1, 2, 3 for X, Y and Z
"Messpunkt 2" (lower table) belongs to the channels 4, 5, 6 for X, Y and Z
On the right you will find the information with which frequency weighting and what weighting the
Channels were calculated. For some evaluations (i.e. whole body vibrations) different weightings are used for different X, Y, Z directions (Wd for X and Y with weighting 1.4).
Here the comparison with the standard (error margin is ± 10%, amplitude of the channels is 100, weighting is 1.0 because frequency weighting is Wf , not Wd):
Number of tone pulses per repetition period
|
Channel |
RMS value Wf according to ISO8041 |
RMS value Wf* 100 * weighting 1.0 |
Display in NeVib |
Difference |
1 |
Analog In 1 (channel group1 X) |
0.0197 |
1.97 |
1.9776 |
0.39 % |
2 |
Analog In 2 (channel group1 Y) |
0.0236 |
2.36 |
2.3209 |
-1.66 % |
4 |
Analog In 3 (channel group1 Z) |
0.0304 |
3.04 |
3.061 |
0.69 % |
8 |
Analog In 4 (channel group2 X) |
0.0416 |
4.16 |
4.1496 |
- 0.25 % |
16 |
Analog In 5 (channel group2 Y) |
0.0571 |
5.71 |
5.7376 |
0.48 % |
Continuous signal |
Analog In 6 (channel group2 Z) |
0.176 |
17.6 |
17.5014 |
- 0.56 % |