Mercurial > hg > aim92
comparison man/man1/acf.1 @ 0:5242703e91d3 tip
Initial checkin for AIM92 aimR8.2 (last updated May 1997).
author | tomwalters |
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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 | |
28 | |
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. | |
80 | |
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