annotate man/man1/acf.1 @ 0:5242703e91d3 tip

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

.TH ACF 1 "15 September 1993"

.SH NAME
acf \- autocorrelation function of contiguous frames.
.nf
i/p and o/p data in binary shorts, (o/p data n/2 points per frame).
.fi

.SH SYNTAX 
acf  [arguments]  [file]


.SH DESCRIPTION
The autocorrelation function (acf) is computed using the fft.
The output framewidth is the given maximum acf lag, which must not be
greater than the input framewidth.
Each input frame is padded with zeroes to the next power of 2 larger than
either the input framewidth, or twice the required max acf lag, (whichever
is  the larger).
If necessary, extra padding can be enforced using the (silent) padding option
to add extra zeroes, padding to a larger power of 2.
The amount of extra padding is "exponential", expanding the basic size to:
   
      ( framesize + padding ) * 2**n

where the padding option is n.


(n=0 by default, so that no extra padding is added. When n=1 then padding is
added to double the size, and when n=2 the size is quadrupled, etc.).
The input and output frame sizes in sample points may be printed using the
"size" option.


.SH EXAMPLES
.nf
1. To print the input and output frame sizes in sample points, 
   eg for a subsequent plotting program, use the size option:

acf ... size=on


2. An acf of a waveform sampled at 10kHz, computed to a max lag 
   of 12.8ms within a frame of 12.8ms, plotting the 2nd frame in 
   a sequence of frames with frameshift 12.8ms.

acf samp=10kHz width=12.8ms frstep=12.8ms frame=2 lag=12.8ms file 
    | x11plot

3. An animated plot of successive acf's of a waveform sampled at 
   10kHz, each computed within a frame of 12.8ms, and shifted by 
   2 sample points.

acf samp=10kHz width=12.8ms frstep=2p lag=12.8ms file 
    | x11play -n128

.fi

.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.