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filter

PURPOSE ^

FILTER overides the filter function for analysis objects.

SYNOPSIS ^

function varargout = filter(varargin)

DESCRIPTION ^

 FILTER overides the filter function for analysis objects.

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

 DESCRIPTION: FILTER overides the filter function for analysis objects.
              Applies the input digital IIR/FIR filter to the input analysis
              object. If the input analysis object contains a
              time-series (tsdata) then the filter is applied using the normal
              recursion algorithm. The output analysis object contains a tsdata
              object.

              If the input analysis object contains a frequency-series (fsdata)
              then the response of the filter is computed and then multiplied
              with the input frequency series. The output analysis object
              contains a frequency series.

 CALL:        >> [b, filt] = filter(a,pl)
              >> [b, filt] = filter(a,filt,pl)
              >> b = filter(a,pl)

 INPUTS:      pl   - a parameter list
              a    - input analysis object

 OUTPUTS:     filt - a copy of the input filter object with the
                     history values filled in.
              b    - output analysis object containing the filtered data.

 PARAMETERS:  filter - the filter object to use to filter the data

 VERSION:     $Id: filter.m,v 1.24 2008/01/21 15:50:26 hewitson Exp $

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

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

 HISTORY: 11-02-07 M Hewitson
             Creation

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

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:

SUBFUNCTIONS ^

SOURCE CODE ^

0001 function varargout = filter(varargin)
0002 % FILTER overides the filter function for analysis objects.
0003 %
0004 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
0005 %
0006 % DESCRIPTION: FILTER overides the filter function for analysis objects.
0007 %              Applies the input digital IIR/FIR filter to the input analysis
0008 %              object. If the input analysis object contains a
0009 %              time-series (tsdata) then the filter is applied using the normal
0010 %              recursion algorithm. The output analysis object contains a tsdata
0011 %              object.
0012 %
0013 %              If the input analysis object contains a frequency-series (fsdata)
0014 %              then the response of the filter is computed and then multiplied
0015 %              with the input frequency series. The output analysis object
0016 %              contains a frequency series.
0017 %
0018 % CALL:        >> [b, filt] = filter(a,pl)
0019 %              >> [b, filt] = filter(a,filt,pl)
0020 %              >> b = filter(a,pl)
0021 %
0022 % INPUTS:      pl   - a parameter list
0023 %              a    - input analysis object
0024 %
0025 % OUTPUTS:     filt - a copy of the input filter object with the
0026 %                     history values filled in.
0027 %              b    - output analysis object containing the filtered data.
0028 %
0029 % PARAMETERS:  filter - the filter object to use to filter the data
0030 %
0031 % VERSION:     $Id: filter.m,v 1.24 2008/01/21 15:50:26 hewitson Exp $
0032 %
0033 % The following call returns a parameter list object that contains the
0034 % default parameter values:
0035 %
0036 % >> pl = filter(ao, 'Params')
0037 %
0038 % HISTORY: 11-02-07 M Hewitson
0039 %             Creation
0040 %
0041 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
0042 
0043 % Standard history variable
0044 ALGONAME = mfilename;
0045 VERSION  = '$Id: filter.m,v 1.24 2008/01/21 15:50:26 hewitson Exp $';
0046 
0047 %% Check if this is a call for parameters
0048 if nargin == 2
0049   if isa(varargin{1}, 'ao') && ischar(varargin{2})
0050     in = char(varargin{2});
0051     if strcmp(in, 'Params')
0052       varargout{1} = getDefaultPL();
0053       return
0054     elseif strcmp(in, 'Version')
0055       varargout{1} = VERSION;
0056       return
0057     end
0058   end
0059 end
0060 
0061 %% capture input variable names
0062 fobj   = [];
0063 bs     = [];
0064 
0065 % Collect input ao's, plist's and ao variable names
0066 in_names = {};
0067 for ii = 1:nargin
0068   in_names{end+1} = inputname(ii);
0069 
0070   if isa(varargin{ii}, 'miir') || isa(varargin{ii}, 'mfir')
0071     fobj = varargin{ii};
0072   end
0073 end
0074 
0075 [as, ps, invars] = collect_inputs(varargin, in_names);
0076 
0077 if isa(ps, 'plist')
0078   pl = combine(ps);
0079 else
0080   pl = plist();
0081 end
0082 if isempty(fobj)
0083   fobj = find(pl, 'filter');
0084 end
0085 
0086 % check inputs
0087 if ~isa(fobj, 'miir') && ~isa(fobj, 'mfir')
0088   error('### the filter input should be an miir/mfir object.');
0089 end
0090 
0091 for j=1:numel(as)
0092 
0093   % get input data
0094   a = as(j);
0095   d = a.data;
0096 
0097   %--------- Time-series filter
0098   %
0099   if isa(d, 'tsdata')
0100 
0101     % get input data
0102     fs = d.fs;
0103 
0104     if isa(fobj, 'mfir')
0105 
0106       % apply filter
0107       disp('* filtering with FIR filter...');
0108       G  = get(fobj, 'gain');
0109 
0110       %     [fstruct, y] = ltpda_firfilter(struct(filt), d.y);
0111       coeffs  = get(fobj, 'a');
0112       Zi      = get(fobj, 'histout');
0113       [y, Zf] = filter(coeffs, 1, G.*d.y, Zi);
0114 
0115       % remove group delay
0116       if isempty(find(pl, 'gdoff'))
0117         gd = floor(get(fobj, 'gd'));
0118         x = d.x(1:end-gd);
0119         y = y(1+gd:end);
0120       else
0121         x = d.x;
0122       end
0123 
0124       % consolodate this structure with mfir class before converting.
0125       fobj = set(fobj, 'histout', Zf.');
0126 
0127     else %if isa(fobj, 'miir')
0128 
0129       if fs ~= get(fobj, 'fs')
0130         warning('!!! Filter is designed for a different sample rate of data.');
0131         % Adjust/redesign if this is a standard filter
0132         fobj = redesign(fobj, fs);
0133       end
0134 
0135       % apply filter
0136 %       [fstruct, y] = ltpda_iirfilter(struct(fobj), d.y, length(d.y));
0137 
0138       acoeffs  = get(fobj, 'a');
0139       bcoeffs  = get(fobj, 'b');
0140       Zi       = get(fobj, 'histout');
0141       [y, Zf] = filter(acoeffs, bcoeffs, d.y, Zi);
0142       x = d.x;
0143       % consolodate this structure with miir class before converting.
0144 %       fobj = set(fobj, 'histin', fstruct.histin);
0145 %       fobj = set(fobj, 'histout', fstruct.histout);
0146       fobj = set(fobj, 'histout', Zf);
0147     end
0148 
0149     %----- Create output analysis object
0150     % make a new tsdata object
0151     ts = tsdata(y, fs);
0152     ts = set(ts, 'name', sprintf('filter %s with %s', d.name, get(fobj,'name')));
0153     ts = set(ts, 'xunits', d.xunits);
0154     ts = set(ts, 'yunits', d.yunits);
0155     ts = set(ts, 't0', d.t0);
0156 
0157     % make a new history object
0158     pl = plist();
0159     pl = append(pl, param('filter', fobj));
0160     h = history(ALGONAME, VERSION, pl, a.hist);
0161     h = set(h, 'invars', cellstr(invars{j}));
0162 
0163     % make output analysis object
0164     b = ao(ts, h);
0165     % name for this object
0166     b  = setnh(b, 'name', sprintf('%s(%s)', get(fobj,'name'), invars{j}));
0167     bs = [bs b];
0168 
0169     %--------- Frequency-series filter
0170     %
0171   elseif isa(d, 'fsdata')
0172     error('### I don''t work yet. Please code me up.');
0173 
0174   else
0175     error('### unknown data type.');
0176   end
0177 end
0178 
0179 % Reshape the ouput to the same size of the input
0180 bs = reshape(bs, size(as));
0181 
0182 if nargout == 1
0183   varargout{1} = bs;
0184 elseif nargout == 2
0185   varargout{1} = bs;
0186   varargout{2} = fobj;
0187 else
0188   error('### wrong number of output arguments.');
0189 end
0190 
0191 %% Get default params
0192 function pl_default = getDefaultPL()
0193 
0194   pl_default = plist(param('filter',  ''));
0195   pl_default = append(pl_default, 'gdoff' ,[]);

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