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Andrew Walshe
06-07-1996, 07:15 PM
Dear subscribers,

I am looking for some information as to the most appropriate method to
determine optimal cutoff frequency (4th Order butterworth filter) for the
smoothing of displacement data associated with a squat movement so it can be
numerically differentiated for further analysis. The data was sampled at
1000Hz and the frequency of the movement is approx 1-2 Hz. I have tried
using the Jacksons Knee Point Method but this seems to give a value which
is too low and shifts the data somewhat. I have been told of another method
advocated by B. Yu, which is apparently more suitable for high sampling
rates but cannot trace a reference. Any insight would be much appreciated.

Thanks to all in advance and as usual a summary of responses will be posted.


Andrew Walshe
Dept. Exercise Science
Southern Cross University
PO BOX 157
Lismore, NSW
Australia
Ph: Int+61+66+203758
FAX: Int+61+66+203880
email: awalshe@scu.edu.au