Mercurial > hg > ltpda

comparison m-toolbox/classes/@ao/ifft_core.m @ 0:f0afece42f48

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Import.
author Daniele Nicolodi <nicolodi@science.unitn.it>
date Wed, 23 Nov 2011 19:22:13 +0100
parents
children
comparison
equal deleted inserted replaced
-1:000000000000 0:f0afece42f48
1 % IFFT_CORE Simple core method which computes the ifft.
2 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3 %
4 % DESCRIPTION: Simple core method which computes the ifft.
5 %
6 % CALL: ao = ifft_core(ao, type)
7 %
8 % INPUTS: ao: Single input analysis object
9 % type: The ifft type
10 % 'symmetric'
11 % 'nonsymmetric'
12 %
13 % VERSION: $Id: ifft_core.m,v 1.6 2011/02/14 19:33:35 ingo Exp $
14 %
15 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
16 function bs = ifft_core(bs, type)
17
18 switch class(bs.data)
19 case {'fsdata'}
20 fs = bs.data.fs;
21 % check fft type
22 if any((bs.data.x)<0) % two sided fft
23 utils.helper.msg(utils.const.msg.PROC1, 'two sided fft');
24 y = ifftshift(bs.data.y);
25 else
26 % get minimum frequency step
27 df = bs.data.x(end)-bs.data.x(end-1);
28 if abs(((fs-df)-bs.data.x(end)))<eps % plain fft
29 utils.helper.msg(utils.const.msg.PROC1, 'plain fft');
30 y = bs.data.y;
31 elseif abs((bs.data.x(end)-fs/2))<eps % onesided fft even nfft
32 utils.helper.msg(utils.const.msg.PROC1, 'one sided fft even nfft');
33 y1 = bs.data.y(1:end);
34 y2 = conj(bs.data.y(end-1:-1:2));
35 if size(y1,1)==1 % raw
36 y = [y1 y2];
37 else
38 y = [y1;y2];
39 end
40 else % onesided fft odd nfft
41 utils.helper.msg(utils.const.msg.PROC1, 'one sided fft odd nfft');
42 y1 = bs.data.y(1:end);
43 y2 = conj(bs.data.y(end:-1:2));
44 if size(y1,1)==1 % raw
45 y = [y1 y2];
46 else
47 y = [y1;y2];
48 end
49 end
50 end
51
52 y = ifft(y, type);
53 % Keep the data shape if the input AO
54 if size(bs.data.y, 1) == 1
55 y = y.';
56 end
57
58 % make a new tsdata object
59 fsd = tsdata(y, fs);
60 fsd.setXunits('s');
61 fsd.setYunits(bs.yunits);
62
63 % Set data
64 bs.data = fsd;
65 % clear errors
66 bs.clearErrors;
67
68 case {'tsdata', 'cdata', 'xydata'}
69 error('### I don''t work for time-series, constant or x/y data.');
70 otherwise
71 error('### unknown data type.')
72 end
73
74
75 end
76
77
78
79