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

Initial checkin for AIM92 aimR8.2 (last updated May 1997).
author tomwalters
date Fri, 20 May 2011 15:19:45 +0100
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1 .TH ACF 1 "15 September 1993"
2
3 .SH NAME
4 acf \- autocorrelation function of contiguous frames.
5 .nf
6 i/p and o/p data in binary shorts, (o/p data n/2 points per frame).
7 .fi
8
9 .SH SYNTAX
10 acf [arguments] [file]
11
12
13 .SH DESCRIPTION
14 The autocorrelation function (acf) is computed using the fft.
15 The output framewidth is the given maximum acf lag, which must not be
16 greater than the input framewidth.
17 Each input frame is padded with zeroes to the next power of 2 larger than
18 either the input framewidth, or twice the required max acf lag, (whichever
19 is the larger).
20 If necessary, extra padding can be enforced using the (silent) padding option
21 to add extra zeroes, padding to a larger power of 2.
22 The amount of extra padding is "exponential", expanding the basic size to:
23
24 ( framesize + padding ) * 2**n
25
26 where the padding option is n.
27
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29 (n=0 by default, so that no extra padding is added. When n=1 then padding is
30 added to double the size, and when n=2 the size is quadrupled, etc.).
31 The input and output frame sizes in sample points may be printed using the
32 "size" option.
33
34
35 .SH EXAMPLES
36 .nf
37 1. To print the input and output frame sizes in sample points,
38 eg for a subsequent plotting program, use the size option:
39
40 acf ... size=on
41
42
43 2. An acf of a waveform sampled at 10kHz, computed to a max lag
44 of 12.8ms within a frame of 12.8ms, plotting the 2nd frame in
45 a sequence of frames with frameshift 12.8ms.
46
47 acf samp=10kHz width=12.8ms frstep=12.8ms frame=2 lag=12.8ms file
48 | x11plot
49
50 3. An animated plot of successive acf's of a waveform sampled at
51 10kHz, each computed within a frame of 12.8ms, and shifted by
52 2 sample points.
53
54 acf samp=10kHz width=12.8ms frstep=2p lag=12.8ms file
55 | x11play -n128
56
57 .fi
58
59 .SH COPYRIGHT
60 .LP
61 Copyright (c) Applied Psychology Unit, Medical
62 Research Council, 1995 .LP Permission to use, copy, modify, and
63 distribute this software without fee is hereby granted for research
64 purposes, provided that this copyright notice appears in all copies
65 and in all supporting documentation, and that the software is not
66 redistributed for any fee (except for a nominal shipping
67 charge). Anyone wanting to incorporate all or part of this software in
68 a commercial product must obtain a license from the Medical Research
69 Council. .LP The MRC makes no representations about the suitability
70 of this software for any purpose. It is provided "as is" without
71 express or implied warranty.
72 .LP
73 THE MRC DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
74 INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
75 EVENT SHALL THE A.P.U. BE LIABLE FOR ANY SPECIAL, INDIRECT OR
76 CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
77 USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
78 OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
79 PERFORMANCE OF THIS SOFTWARE.
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