function h = df2(varargin)
%DF2  Constructor for the direct-form II object.
%   F = DF2(B,A) creates a direct-form II (DF2) object F
%   with numerator coefficients specified in vector B and
%   denominator coefficients specified in vector A.
%
%   F = DF2(B1,A1,B2,A2,...) creates a DF2 object F of
%   cascaded direct-form II Sections. The i-th numerator
%   and denominator are given by the coefficients in
%   vectors Bi and Ai respectively.
%
%   F = DF2({{B1,A1},{B2,A2},...}) is equivalent to
%   F = DF2(B1,A1,B2,A2,...).
%
%   F = DF2(...,C) creates a DF2 object of direct-form
%   II sections connected as indicated in C.  C can be either
%   'cas' (default) for cascaded connections or 'par'
%   for parallel connections.

%   Author(s): R. Losada
%   Copyright 1988-2000 The MathWorks, Inc.
%   $Revision: 1.3 $  $Date: 2000/06/13 21:20:33 $ 

% Constructor may be used as a structure converter to itself, handle this case
htest = dtf(varargin{:});
if isa(htest,'df2'),
    h = htest;
    return
end

h.version = 1;

h = class(h,'df2',dtf(varargin{:}));
