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function varargout = importfilt(action,varargin)
%IMPORTFILT Import function for Filter Structures in the SPTool.
% 'version' - returns string indicating version number for exporting
% data of this type from SPTool.
% 'make' - creates a new object
% [err,errstr,struct] = importfilt('make',{input values})
% 'valid' - test if input struc is a valid filter
% 'fields' - return information about the input fields and field names for
% this type of object in the import dialog.
% [popupString,fields,FsFlag,defaultLabel] = import*('fields')
% struct = importfilt('changeFs',struct,Fs) - change the sampling frequency
% of struct
% newstruct = importfilt('merge',struct1,struct2) - merge struct1 and struct2
% into new struct, retaining client specific fields of struct1 and
% global fields of struct2
% Copyright (c) 1988-98 by The MathWorks, Inc.
% $Revision: 1.1 $
switch action
case 'version'
% versionString = import*('version')
% returns the version of this component (a string). This will be saved in
% any exported SPT data of this type under the SPTIdentifier field
% of the structure:
% .SPTIdentifier.version
% .SPTIdentifier.type <-- obtained from popupString in the 'fields' call.
varargout{1} = '2.0';
case 'fields'
PopupString = 'Filter';
flds(1).form = 'Transfer Function';
flds(1).fields = {'Numerator' 'Denominator'};
flds(1).formTag = 'tf';
flds(2).form = 'State Space';
flds(2).fields = {'A Matrix' 'B Matrix' 'C Matrix' 'D Matrix'};
flds(2).formTag = 'ss';
flds(3).form = 'Zeros, Poles, Gain';
flds(3).fields = {'Zeros' 'Poles' 'Gain'};
flds(3).formTag = 'zpk';
flds(4).form = '2nd Order Sections';
flds(4).fields = {'SOS Matrix'};
flds(4).formTag = 'sos';
FsFlag = 1;
defaultLabel = 'filt';
varargout = {PopupString,flds,FsFlag,defaultLabel};
case 'make'
% [err,errstr,struc] = importsig('make',{input values})
% Inputs:
% {input values} cell array -
% first element is integer giving the value of the 'form' popup
% (e.g. 1==TF, 2==SS, 3=ZPK, etc)
% elements 2..N are MATLAB variables. If FsFlag == 1, the last one
% is the sampling frequency Fs.
% This needs to be the only place you use to create new objects,
% since the fields and their order have to be the same for every object!
err = 0;
errstr = '';
% initialize empty structure:
struc.tf = [];
struc.ss = [];
struc.zpk = [];
struc.sos = [];
struc.imp = [];
struc.step = [];
struc.t = [];
struc.H = [];
struc.G = [];
struc.f = [];
struc.specs = [];
struc.Fs = varargin{1}{end};
switch lower(varargin{1}{1})
case {'tf',1} % TF
struc.tf.num = varargin{1}{2};
struc.tf.den = varargin{1}{3};
case {'ss',2} % SS
struc.ss.a = varargin{1}{2};
struc.ss.b = varargin{1}{3};
struc.ss.c = varargin{1}{4};
struc.ss.d = varargin{1}{5};
struc.tf.num = [];
struc.tf.den = [];
eval(['[struc.tf.num,struc.tf.den]='...
'ss2tf(struc.ss.a,struc.ss.b,struc.ss.c,struc.ss.d);'],...
'err = 1;')
if err
errstr = 'Could not convert A,B,C,D to transfer function form.';
end
case {'zpk',3} % ZPK
struc.zpk.z = varargin{1}{2};
struc.zpk.p = varargin{1}{3};
struc.zpk.k = varargin{1}{4};
struc.tf.num = [];
struc.tf.den = [];
eval(['struc.tf.num = struc.zpk.z(:)*struc.zpk.k;'...
'struc.tf.den = poly(struc.zpk.p(:));'],...
'err = 1;')
if err
errstr = 'Could not convert Z,P,K to transfer function form.';
end
case {'sos',4} % SOS
struc.sos = varargin{1}{2};
struc.tf.num = [];
struc.tf.den = [];
eval(['[struc.tf.num,struc.tf.den]='...
'sos2tf(struc.sos);'],...
'err = 1;')
if err
errstr = 'Could not convert SOS to transfer function form.';
end
end
% Force filter numerator and denominator to be rows.
struc.tf.num = struc.tf.num(:).';
struc.tf.den = struc.tf.den(:).';
if isempty(errstr)
if ~all(size(struc.Fs)==1) | ~isreal(struc.Fs) | struc.Fs<=0
errstr = 'The sampling frequency must be a positive real scalar.';
elseif isempty(struc.tf.num) | isempty(struc.tf.den) | ...
norm(struc.tf.num)==0 | norm(struc.tf.den)==0
errstr = 'The filter must have non-trivial numerator and denominator orders.';
elseif struc.tf.den(1) == 0
errstr = 'First denominator filter coefficient must be non-zero.';
end
end
% --------
if isempty(errstr), err = 0; else err = 1; end
if ~err
struc = importfilt('assignType',struc);
struc.lineinfo = [];
struc.SPTIdentifier.type = 'Filter';
struc.SPTIdentifier.version = importfilt('version');
else
struc = [];
end
struc.label = '';
varargout = {err,errstr,struc};
case 'valid'
% [valid,struc] = import*('valid',struc) - return
% 1 if the input structure is a valid "object", 0 if not.
% input struc assumed to have field SPTIndentifier with fields
% .type, .version, and struc.SPTIndentifier.type is the
% correct string
% Updates the structure if the version is old.
% Also sets '.type' field of struc
% Criteria for validity:
% - structure has the correct fields in the correct order
% - some of the fields are checked for class information
valid = 1; % assume valid on input
struc = varargin{1};
% first test to see if struc can be added to structure array;
% if successful, fields are same and in same order
[err,errstr,vanillaStruc]=importfilt('make',{1 1 1});
eval('vanillaStruc(2)=struc;','valid=0;')
% now assuming the fields are all there, test their contents
% for validity:
if valid
valid = isequal(class(struc.tf.num),'double');
end
if valid
valid = isequal(class(struc.tf.den),'double');
end
if valid
valid = (isequal(class(struc.Fs),'double') & length(struc.Fs) == 1);
end
if valid
struc = importfilt('assignType',struc);
end
if valid
if strcmp(struc.SPTIdentifier.version,'1.0')
struc.specs = fdutil('updateSpecStruc',struc.specs);
struc.SPTIdentifier.version = '2.0';
end
end
varargout = {valid,struc};
return
case 'assignType'
% struc = import*('assignType',struc)
struc = varargin{1};
if isempty(struc.specs)
struc.type = 'imported';
else
if isempty(struc.specs.currentModule) | ...
~strcmp(struc.specs.currentModule,'fdpzedit')
struc.type = 'design';
else
struc.type = 'imported';
end
end
varargout{1} = struc;
%----------------------------------------------------------------------------
% struct = importfilt('changeFs',struct,Fs) - change the sampling frequency
% of struct
case 'changeFs'
struc = varargin{1};
newFs = varargin{2};
oldFs = struc.Fs;
if ~isempty(struc.f)
struc.f = struc.f*newFs/oldFs;
end
struc.Fs = newFs;
varargout{1} = struc;
%----------------------------------------------------------------------------
% newstruct = importfilt('merge',struct1,struct2) - merge struct1 and struct2
% into new struct, retaining client specific fields of struct1 and
% global fields of struct2
% This callback is provided for when you import a new structure via
% the import dialog and there is already a structure in the SPTool that
% has this name. Some of the fields (eg, 'data' and 'Fs')
% are global and need to be changed by this action, others which are
% controlled by the clients (eg, 'lineinfo', 'specs' and 'label') may not.
%
% Both are assumed valid structures on input.
case 'merge'
struct1 = varargin{1};
struct2 = varargin{2};
newstruct = struct2;
if isempty(struct2.lineinfo)
newstruct.lineinfo = struct1.lineinfo;
end
if isempty(struct2.specs)
newstruct.specs = struct1.specs;
end
varargout{1} = newstruct;
end