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View Full Version : Re: Linear enveloping of EMG



Dr. Chris Kirtley
08-31-2000, 02:15 AM
Dear At, Matthew, Jason, Drew, and others,

As usual, a simple question turns out to be quite complex!

I still say that the main operation in the linear envelope is the
(strangely-enough) non-linear rectification stage. Without this one
could not have an envelope at all.

The envelope (low frequency shape superimposed on the high frequency
spikes) is then smoothed to a greater or lesser extent by the filter. As
At points out, the nature of the appropriate filter ad precise cut-off
frequency used will depend on the behavior of the muscle at the time.

Incidentally, I have always wondered why the LINEAR envelope is so named
- what is linear about it?

Chris
--
Dr. Chris Kirtley MD PhD
Associate Professor
HomeCare Technologies for the 21st Century (Whitaker Foundation)
NIDRR Rehabilitation Engineering Research Center on TeleRehabilitation
Dept. of Biomedical Engineering, Pangborn 105B
Catholic University of America
620 Michigan Ave NE
Washington, DC 20064
Tel. 202-319-6247, fax 202-319-4287
Email: kirtley@cua.edu
http://engineering.cua.edu/biomedical

Clinical Gait Analysis: http://guardian.curtin.edu.au/cga
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