View Full Version : Signal Smoothing Techniques

05-15-2007, 01:53 PM
Dear all,

I am interested in sampling analogue voltage signals (mainly force and
position) from an isokinetic device with a NI PXI system using Labview
software. I would like to use a single Labview VI to sample ALL
isokinetic data that I may collect (everything from isometric MVCs to
evoked twitch properties) as it will make all my data collect very
simple. Creating the V is fairly straight forward, however I do have a
concern about signal processing prior to data sampling.

What is the best method for me to smooth the voltage signals in Labview?
I am aware that using a Moving Average Window may be ok for voluntary
testing, but may not be so good for recording evoked twitch responses
(due to the short contractile times and the influence of averaging on
signal amplitude and temporal characteristics). Currently, I have set up
a 5Hz low-pass filter, which does the trick very nicely. But I thought
this may be too aggressive.

Or should I create a separate VI for each condition (ie voluntary and
evoked twitch) which both use different signal smoothing techniques.

Any feedback you could provide would be greatly appreciated.

Kind regards,

************************************************** *********************
Dr Jack Cannon
BSocSci(Hons), GradDipEd, PhD
Bachelor of Exercise Science Course Coordinator
Lecturer in Motor Control and Learning
School of Human Movement Studies
Faculty of Education
Charles Sturt University
Panorama Avenue
Bathurst 2795
* (02) 6338 4334
* (02) 6338 4065
* jcannon@csu.edu.au
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