mixed.m

数字通信第四版原书的例程

function [ret,x0,str]=mixeds(t,x,u,flag);
%MIXEDS	is the M-file description of the SIMULINK system named MIXEDS.
%	The block-diagram can be displayed by typing: MIXEDS.
%
%	SYS=MIXEDS(T,X,U,FLAG) returns depending on FLAG certain
%	system values given time point, T, current state vector, X,
%	and input vector, U.
%	FLAG is used to indicate the type of output to be returned in SYS.
%
%	Setting FLAG=1 causes MIXEDS to return state derivitives, FLAG=2
%	discrete states, FLAG=3 system outputs and FLAG=4 next sample
%	time. For more information and other options see SFUNC.
%
%	Calling MIXEDS with a FLAG of zero:
%	[SIZES]=MIXEDS([],[],[],0),  returns a vector, SIZES, which
%	contains the sizes of the state vector and other parameters.
%		SIZES(1) number of states
%		SIZES(2) number of discrete states
%		SIZES(3) number of outputs
%		SIZES(4) number of inputs.
%	For the definition of other parameters in SIZES, see SFUNC.
%	See also, TRIM, LINMOD, LINSIM, EULER, RK23, RK45, ADAMS, GEAR.

% Note: This M-file is only used for saving graphical information;
%       after the model is loaded into memory an internal model
%       representation is used.

%	Copyright (c) 1990-94 by The MathWorks, Inc.

% the system will take on the name of this mfile: 
sys = mfilename;
new_system(sys)
simver(1.3)
if(0 == (nargin + nargout))
     set_param(sys,'Location',[14,58,382,193])
     open_system(sys)
end;
set_param(sys,'algorithm',		'RK-45')
set_param(sys,'Start time',	'0.0')
set_param(sys,'Stop time',		'999999')
set_param(sys,'Min step size',	'0.0001')
set_param(sys,'Max step size',	'10')
set_param(sys,'Relative error','1e-3')
set_param(sys,'Return vars',	'')

add_block('built-in/Integrator',[sys,'/','Cint'])
set_param([sys,'/','Cint'],...
		'Initial','1',...
		'position',[120,18,140,62])

add_block('built-in/Outport',[sys,'/','Outport'])
set_param([sys,'/','Outport'],...
		'position',[255,30,275,50])

add_block('built-in/Unit Delay',[sys,'/','Dint'])
set_param([sys,'/','Dint'],...
		'x0','1',...
		'position',[185,14,205,66])

add_block('built-in/Inport',[sys,'/','Inport'])
set_param([sys,'/','Inport'],...
		'position',[55,30,75,50])
add_line(sys,[145,40;175,40])
add_line(sys,[80,40;110,40])
add_line(sys,[210,40;245,40])
% Return any arguments.
if (nargin | nargout)
	% Must use feval here to access system in memory
	if (nargin > 3)
		if (flag == 0)
			eval(['[ret,x0,str]=',sys,'(t,x,u,flag);'])
		else
			eval(['ret =', sys,'(t,x,u,flag);'])
		end
	else
		[ret,x0,str] = feval(sys);
	end
end