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comparison m-toolbox/classes/@mfir/fromAO.m @ 0:f0afece42f48

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author Daniele Nicolodi <nicolodi@science.unitn.it>
date Wed, 23 Nov 2011 19:22:13 +0100
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-1:000000000000 0:f0afece42f48
1 % create FIR filter from magnitude of input AO/fsdata
2 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3 %
4 % FUNCTION: mfirFromAO
5 %
6 % DESCRIPTION: create FIR filter from magnitude of input AO/fsdata
7 %
8 % CALL: f = mfirFromAO(a, pli, version, algoname)
9 %
10 % PARAMETER: a: Analysis object
11 % pli: Parameter list object
12 % version: cvs version string
13 % algoname: The m-file name (use the mfilename command)
14 %
15 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
16
17 function filt = fromAO(filt, pli)
18
19 import utils.const.*
20
21 VERSION = '$Id: fromAO.m,v 1.25 2011/08/15 11:37:04 hewitson Exp $';
22 ii = mfir.getInfo('mfir', 'From AO');
23 % Set the method version string in the minfo object
24 ii.setMversion([VERSION '-->' ii.mversion]);
25
26 % Add default values
27 pl = applyDefaults(ii.plists, pli);
28
29 % Get parameters
30 a = find(pl, 'AO');
31 N = find(pl, 'N');
32 win = find(pl, 'Win');
33 method = find(pl, 'method');
34
35 if ischar(win)
36 name = win;
37 wlen = pl.find('length');
38 % if the plist contains a window length (like history plists do), use
39 % it; otherwise use the filter order N.
40 if isempty(wlen)
41 wlen = N;
42 end
43
44 if strcmpi(name, 'kaiser')
45 psll = pl.find('psll');
46 win = specwin(name, wlen, psll);
47 else
48 win = specwin(name, wlen);
49 end
50 end
51
52 % Check that a.data is a fsdata object
53 if ~isa(a.data, 'fsdata')
54 error('### Please use an analysis object with a fsdata data object to create a mfir object.');
55 end
56
57 fs = a.data.fs;
58 f = a.data.getX;
59 xx = abs(a.data.getY);
60
61 ffm = f/(fs/2);
62 switch lower(method)
63 case 'frequency-sampling'
64 % check window
65 if ischar(win)
66 if strcmpi(win, 'kaiser')
67 win = specwin(win, N+1, win.psll);
68 else
69 win = specwin(win, N+1);
70 end
71 end
72
73 if length(win.win) ~= N+1
74 warning('!!! resizing window function to match desired filter order.');
75 if strcmpi(win.type, 'Kaiser')
76 win = specwin(win.type, N+1, win.psll);
77 else
78 win = specwin(win.type, N+1);
79 end
80 end
81 utils.helper.msg(msg.OPROC2, 'designing filter using frequency-sampling method [help fir2]');
82 mtaps = fir2(N, ffm, xx, win.win);
83 case 'least-squares'
84 error('### this design method is not working properly yet.');
85 if mod(length(ffm),2)
86 ffm = ffm(1:end-1);
87 xx = xx(1:end-1);
88 end
89 utils.helper.msg(msg.OPROC2, 'designing filter using least-squares method [help firls]');
90 mtaps = firls(N, ffm, xx);
91 case 'parks-mcclellan'
92 error('### this design method is not working properly yet.');
93 utils.helper.msg(msg.OPROC2, 'designing filter using Parks-McClellan method [help firpm]');
94 mtaps = firpm(N, ffm, xx);
95 otherwise
96 error('### unknown filter design method.');
97 end
98
99 % Make mfir object
100 filt.fs = fs;
101 filt.a = mtaps;
102 filt.gd = (filt.ntaps+1)/2;
103 filt.histout = zeros(1,filt.ntaps-1);
104
105 % Override some properties of the input plist
106 if isempty(pl.find('name'))
107 pl.pset('name', sprintf('fir(%s)', a.name));
108 end
109 if isempty(pl.find('description'))
110 pl.pset('description', a.description);
111 end
112
113 % Add history
114 pl.remove('AO'); % because the input AO goes in the history
115 filt.addHistory(ii, pl, [], a.hist);
116
117 % Set object properties
118 filt.setObjectProperties(pl);
119
120 end % function f = mfirFromAO(a, pli, version, algoname)