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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 1.10 2008/01/20 12:53:29 hewitson 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 1.10 2008/01/20 12:53:29 hewitson 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 1.10 2008/01/20 12:53:29 hewitson Exp $';
0024 bs       = [];
0025 
0026 % Check if this is a call for parameters
0027 if nargin == 2
0028   if isa(varargin{1}, 'ao') && ischar(varargin{2})
0029     in = char(varargin{2});
0030     if strcmp(in, 'Params')
0031       varargout{1} = getDefaultPL();
0032       return
0033     elseif strcmp(in, 'Version')
0034       varargout{1} = VERSION;
0035       return
0036     end
0037   end
0038 end
0039 
0040 % Collect input ao's, plist's and ao variable names
0041 in_names = {};
0042 for ii = 1:nargin
0043   in_names{end+1} = inputname(ii);
0044 end
0045 
0046 [as, ps, invars] = collect_inputs(varargin, in_names);
0047 
0048 
0049 % Check input analysis object
0050 for j=1:numel(as)
0051   a     = as(j);
0052   d     = get(a, 'data');
0053   dinfo = whos('d');
0054 
0055   % Which data type do we have
0056   dtype = dinfo.class;
0057   switch dtype
0058     case 'tsdata'
0059 
0060       % make a new fsdata object
0061       nfft = length(d.y);
0062       ft   = fft(d.y);
0063       ft   = ft(1:nfft/2+1);
0064       f    = linspace(0, d.fs/2, length(ft));
0065       fsd = fsdata(f, ft, d.fs);
0066       fsd = set(fsd, 'name', sprintf('fft(%s)', d.name));
0067       fsd = set(fsd, 'xunits', 'Hz');
0068       fsd = set(fsd, 'yunits', '');
0069 
0070       % make a new history object
0071       h = history(ALGONAME, VERSION, plist(), [a.hist]);
0072       h = set(h, 'invars', cellstr(invars{j}));
0073 
0074       % make output analysis object
0075       b = ao(fsd, h);
0076       b = setnh(b, 'name', sprintf('fft(%s)', invars{j}));
0077 
0078     case {'fsdata', 'cdata', 'xydata'}
0079       error('### I don''t work for frequency-series, xy and constant data yet.');
0080       disp('* FFT of fsdata object');
0081 
0082 
0083     otherwise
0084       error('### unknown data type. They can not be addded.')
0085   end
0086 
0087   % add to output
0088   bs = [bs b];
0089 end
0090 
0091 % Reshape the ouput to the same size of the input
0092 bs = reshape(bs, size(as));
0093 
0094 varargout{1} = bs;
0095 
0096 
0097 %--------------------------------------------------------------------------
0098 % Get default params
0099 function plo = getDefaultPL()
0100 
0101 plo = plist();
0102 
0103 % END

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