diff man/man1/racf.1 @ 0:5242703e91d3 tip

Initial checkin for AIM92 aimR8.2 (last updated May 1997).

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+++ b/man/man1/racf.1	Fri May 20 15:19:45 2011 +0100
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+.TH RACF 1 "1 September 1993"
+
+.SH NAME
+racf \- recursive autocorrelation function of contiguous frames.
+
+.SH SYNTAX 
+racf  [arguments]  [file]
+
+.SH DESCRIPTION
+Autocorrelation function using a recursive "leaky integrator" filter.
+For the m'th lag, the n'th recursive update is:
+
+.nf
+      y[n] = a.y[n-1] + (1-a).f[n].f[n-m]
+.fi
+
+where decay constant a = exp(-Ts/T),
+Ts is the sample interval in seconds, and T  is the decay time constant in seconds.
+
+The recursion computes the mean value of the product f[n].f[n-m]
+within an exponential window which weights past values.
+The window width parameter (eg. corresponding with the width of the
+fft analysis window) is the time constant parameter.
+The half life of the exponential window is given by -T.ln(0.5) = 0.693T
+ie. for a given time constant, T secs, the window decays to half of its
+current value in a period of 0.693T secs.
+Similarly, the window decays by 99% of its initial value in about 4.6T secs.
+So T can be set to accomodate an expected period.
+
+The routine generates the autocovariance function.
+An optional normalization (dividing each coefficient by the zeroth
+coefficient) produces the autocorrelation function,
+(and this is then scaled up to the range [0-1000]).
+
+The output framewidth is the given maximum acf lag.
+
+.SH "SEE ALSO"
+options acf acgram
+
+.SH COPYRIGHT
+.LP
+Copyright (c) Applied Psychology Unit, Medical Research Council, 1995
+.LP
+Permission to use, copy, modify, and distribute this software without fee 
+is hereby granted for research purposes, provided that this copyright 
+notice appears in all copies and in all supporting documentation, and that 
+the software is not redistributed for any fee (except for a nominal 
+shipping charge). Anyone wanting to incorporate all or part of this 
+software in a commercial product must obtain a license from the Medical 
+Research Council.
+.LP
+The MRC makes no representations about the suitability of this 
+software for any purpose.  It is provided "as is" without express or 
+implied warranty.
+.LP
+THE MRC DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING 
+ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL 
+THE A.P.U. BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES 
+OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, 
+WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, 
+ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 
+SOFTWARE.
+