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fft

PURPOSE ^

FFT overloads the fft operator for Analysis objects.

SYNOPSIS ^

function varargout = fft(varargin)

DESCRIPTION ^

 FFT overloads the fft operator for Analysis objects.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

 DESCRIPTION: FFT overloads the fft operator for Analysis objects.

 CALL:        b = fft(a)

 VERSION:     $Id: fft.m,v 1.6 2007/11/02 13:17:41 ingo Exp $

 The following call returns a parameter list object that contains the
 default parameter values:

 >> pl = fft(ao, 'Params')

 HISTORY: 12-03-07 M Hewitson
             Creation

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:

SUBFUNCTIONS ^

SOURCE CODE ^

0001 function varargout = fft(varargin)
0002 % FFT overloads the fft operator for Analysis objects.
0003 %
0004 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
0005 %
0006 % DESCRIPTION: FFT overloads the fft operator for Analysis objects.
0007 %
0008 % CALL:        b = fft(a)
0009 %
0010 % VERSION:     $Id: fft.m,v 1.6 2007/11/02 13:17:41 ingo Exp $
0011 %
0012 % The following call returns a parameter list object that contains the
0013 % default parameter values:
0014 %
0015 % >> pl = fft(ao, 'Params')
0016 %
0017 % HISTORY: 12-03-07 M Hewitson
0018 %             Creation
0019 %
0020 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
0021 
0022 ALGONAME = mfilename;
0023 VERSION  = '$Id: fft.m,v 1.6 2007/11/02 13:17:41 ingo Exp $';
0024 
0025 % Check if this is a call for parameters
0026 if nargin == 2
0027   if isa(varargin{1}, 'ao') && ischar(varargin{2})
0028     in = char(varargin{2});
0029     if strcmp(in, 'Params')
0030       varargout{1} = getDefaultPL();
0031       return
0032     elseif strcmp(in, 'Version')
0033       varargout{1} = VERSION;
0034       return
0035     end
0036   end
0037 end
0038 
0039 % capture input variable names
0040 invars = {};
0041 for j=1:nargin
0042   if isa(varargin{j}, 'ao')
0043     invars = [invars cellstr(inputname(j))];
0044   end
0045 end
0046 
0047 % Get inputs
0048 as      = [];
0049 ps      = [];
0050 bs      = [];
0051 
0052 for j=1:nargin
0053   if isa(varargin{j}, 'ao')
0054     as = [as varargin{j}];
0055   end
0056   if isa(varargin{j}, 'plist')
0057     ps = [ps varargin{j}];
0058   end
0059 end
0060 
0061 % Check input analysis object
0062 for j=1:numel(as)
0063   a     = as(j);
0064   d     = get(a, 'data');
0065   dinfo = whos('d');
0066 
0067   % Which data type do we have
0068   dtype = dinfo.class;
0069   switch dtype
0070     case 'tsdata'
0071       disp('* FFT of tsdata object');
0072 
0073       % make a new fsdata object
0074       nfft = length(d.x);
0075       ft   = fft(d.x);
0076       ft   = ft(1:nfft/2+1);
0077       f    = linspace(0, d.fs/2, length(ft));
0078       fsd = fsdata(f, ft, d.fs);
0079       fsd = set(fsd, 'name', sprintf('fft(%s)', d.name));
0080       fsd = set(fsd, 'xunits', 'Hz');
0081       fsd = set(fsd, 'yunits', '');
0082 
0083       % make a new history object
0084       h = history(ALGONAME, VERSION, plist(), [a.hist]);
0085       h = set(h, 'invars', invars);
0086 
0087       % make output analysis object
0088       b = ao(fsd, h);
0089       if j > length(invars)
0090         n = a.name;
0091       else
0092         n = invars{j};
0093       end
0094       b = setnh(b, 'name', sprintf('fft(%s)', n));
0095 
0096     case {'fsdata', 'cdata', 'xydata'}
0097       error('### I don''t work for frequency-series, xy and constant data yet.');
0098       disp('* FFT of fsdata object');
0099 
0100 
0101     otherwise
0102       error('### unknown data type. They can not be addded.')
0103   end
0104 
0105   % add to output
0106   bs = [bs b];
0107 end
0108 
0109 % Reshape the ouput to the same size of the input
0110 bs = reshape(bs, size(as));
0111 
0112 varargout{1} = bs;
0113 
0114 
0115 %--------------------------------------------------------------------------
0116 % Get default params
0117 function plo = getDefaultPL()
0118 
0119 plo = plist();
0120 
0121 % END

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