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comparison m-toolbox/classes/@ao/ltf_plan.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 % LTF_PLAN computes all input values needed for the LPSD and LTFE algorithms.
2 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3 %
4 % DESCRIPTION: LTF_PLAN computes all input values needed for the LPSD and LTFE
5 % algorithms.
6 %
7 % CALL: [f, r, b, L, K] = ltf_plan(Ndata, fs, olap, bmin, Lmin, Jdes, Kdes)
8 %
9 % INPUTS: Ndata - the length of the time-series to be processed
10 % fs - the sample rate of the time-series to be processed
11 % olap - overlap percentage, usually taken from the window function
12 % bmin - the minimum bin number to be used. This is usually taken
13 % from the window function.
14 % Lmin - The minimum segment length.
15 % Jdes - the desired number of frequencies.
16 % Kdes - The desired number of averages.
17 %
18 % OUTPUTS: Each output is a vector, one value per frequency:
19 % f - the frequency
20 % r - frequency resolution (Hz)
21 % b - bin number
22 % L - segment lengths
23 % K - number of averages
24 %
25 % PARAMETER LIST:
26 %
27 % VERSION: $Id: ltf_plan.m,v 1.6 2009/08/31 17:09:43 ingo Exp $
28 %
29 % HISTORY: 19-02-2008 M Hewitson
30 % Creation
31 %
32 % REFERENCE: "lpsd revisited: ltf" / S2-AEI-TN-3052
33 % 2008/02/07 V1.1
34 % G Heinzel
35 %
36 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
37
38 % q - a vector of start indices for the segments
39
40 function varargout = ltf_plan(varargin)
41
42 %% ------ Check inputs ------------------------------------------------
43 if nargin ~= 7 || nargout ~= 5
44 help(mfilename)
45 error('### Incorrect usage');
46 end
47
48 Ndata = varargin{1};
49 fs = varargin{2};
50 olap = varargin{3};
51 bmin = varargin{4};
52 Lmin = varargin{5};
53 Jdes = varargin{6};
54 Kdes = varargin{7};
55
56 %% ------ Set up some variables -------------------------------------------
57
58 xov = (1 - olap/100);
59 fmin = fs / Ndata * bmin;
60 fmax = fs/2;
61 fresmin = fs / Ndata;
62 freslim = fresmin * (1+xov*(Kdes-1));
63 logfact = (Ndata/2)^(1/Jdes) - 1;
64
65
66
67 %% ------ Prepare outputs -------------------------------------------
68
69 f = [];
70 r = [];
71 b = [];
72 L = [];
73 K = [];
74 % q = [];
75
76 %% ------ Loop over frequency -------------------------------------------
77 fi = fmin;
78 while fi < fmax
79
80 fres = fi * logfact;
81 if fres <= freslim
82 fres = sqrt(fres*freslim);
83 end
84 if fres < fresmin
85 fres = fresmin;
86 end
87
88 bin = fi/fres;
89 if bin < bmin
90 bin = bmin;
91 fres = fi/bin;
92 end
93
94 dftlen = round(fs / fres);
95 if dftlen > Ndata
96 dftlen = Ndata;
97 end
98 if dftlen < Lmin
99 dftlen = Lmin;
100 end
101
102 nseg = round((Ndata - dftlen) / (xov*dftlen) + 1);
103 if nseg == 1
104 dftlen = Ndata;
105 end
106
107 fres = fs / dftlen;
108 bin = fi / fres;
109
110 % Store outputs
111 f = [f fi];
112 r = [r fres];
113 b = [b bin];
114 L = [L dftlen];
115 K = [K nseg];
116
117 fi = fi + fres;
118
119 end
120
121 %% ------ Set outputs -------------------------------------------
122
123 varargout{1} = f.';
124 varargout{2} = r.';
125 varargout{3} = b.';
126 varargout{4} = L.';
127 varargout{5} = K.';
128 end
129