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Level crossings

04 Nov 2009

Detect level crossing of signals.

File Information
Description	LC_FAST calculates how many times a given input signal crosses a set of levels. It is much faster than traditional algorithms being designed to handle big datasets.
MATLAB release	MATLAB 7.6 (R2008a)
Zip File Content
Other Files	lc_fast.m, license.txt

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Everyone's Tags	data exploration, data export, data import, level crossing, level crossing method, level crossing rate, level detect, mathematics, signal processing, statistics, zero crossing, zero detect
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Comments and Ratings (3)
05 Nov 2009	Martin Lechner	This function has problems with consecutive equal values. They are also counted as crossings. lc_fast([0;1;1;1;1;1;0],1) ans = 4 I would expect for the example above: 1
05 Nov 2009	Jos (10584)	Just curious what you mean by "This algorithm is generally faster than traditional ones". What are the traditonal ones? I would suspect that an operation using something using DIFF and SIGN, as in (not-tested) "sum(diff(sign(Signal-OneLevel))) ~= 0)" is faster (as well as shorter)
05 Nov 2009	roberto madia	"Traditional" algorithms means algorithms based on sum(diff(sign(Signal-OneLevel))) ~= 0) method. For large datasets this routine is at least 5 times faster. In case of consecutive equal values this routines calculates all crossings even tough they are all equals.

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Tag Activity for this File
Tag	Applied By	Date/Time
data export	roberto madia	04 Nov 2009 09:34:55
zero crossing	roberto madia	04 Nov 2009 09:34:56
mathematics	roberto madia	04 Nov 2009 09:34:56
signal processing	roberto madia	04 Nov 2009 09:34:56
statistics	roberto madia	04 Nov 2009 09:34:56
data exploration	roberto madia	04 Nov 2009 09:34:56
data import	roberto madia	04 Nov 2009 09:34:56
level crossing	roberto madia	04 Nov 2009 09:34:56
zero detect	roberto madia	04 Nov 2009 09:34:56
level detect	roberto madia	04 Nov 2009 09:34:56
level crossing method	roberto madia	04 Nov 2009 09:34:56
level crossing rate	roberto madia	04 Nov 2009 09:34:56

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