function data = source(fr_length,frames,md,zf,varargin)%SOURCE Generate source data.%   D = SOURCE(K,F,MD,ZF) creates a data source consists of desired%   number of F frames each having K symbols. MD determines the range of%   integers (data) the source will be filled with. For instance of MD=4,%   D will contain numbers within a set { 0,1,2,3}. ZF corresponds to%   the number of zeros that will be appended at the end of each frame.%   This ensures the encoder will be forced into the zero state at the%   beginning and end of each frame. %%   D = SOURCE(...,'PropertyName',PropertyValue,...)%%   Source Property List%%   Pattern        {'rand'} | 'ramp' | 'const'%   Const          value%   Echo           'on' | {'off'}%%   See also SPACE.%   Copyright 2001-2003 Kamil Anis, anisk@feld.cvut.cz%   Dept. of Radioelectronics, %   Faculty of Electrical Engineering%   Czech Technical University in Prague%   $Revision: 2.1 $  $Date: 2003/1/16 17:33:28 $%   --%   <additional stuff goes here>global ECHOname = 'SOURCE';[idt,tag] = iecho(name);nopts = length(varargin) / 2;opts = reshape(varargin,[2 nopts])';ord1 = strmatch('Echo',opts(:,1));ord2 = strmatch('Pattern',opts(:,1));ord3 = strmatch('Const',opts(:,1));% Echoif ~isempty(ord1) % first check whether local option exists	value1 = opts{ord1,2};	switch value1	case 'on'		ech = 1;	case 'off'		ech = 0;	otherwise		disp(' ');		disp([tag,'Invalid option for Echo property.']);		disp([idt,'Possible values are ''on''|{''off''}.']);		disp(' ');		ech = 0;	endelse	if ~isempty(ECHO) % than check whether global option exists		switch ECHO		case 'on'			ech = 1;		case 'off'			ech = 0;		otherwise			disp(' ');			disp([tag,'Invalid option for Echo property.']);			disp([idt,'Possible values are ''on''|{''off''}.']);			disp(' ');			ech = 0;		end	else % if there are no settings use the defaults		ech = 0; % default value	endend% Patternif isempty(ord2) % there's no such option	mode = 'rand'; % default valueelse % there's relevant option	mode = opts{ord2,2};end% Constif isempty(ord3) % there's no such option	const = 1; % default valueelse % there's relevant option	const = opts{ord3,2};end%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% BODY BEGIN %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%switch modecase 'rand'	data = round((md - 1) * rand(fr_length,1,frames));case 'ramp'	ramp = mod([1:fr_length] - 1,md)';	data = repmat(ramp,[1 1 frames]);case 'const'	data = varargin{1} * ones(fr_length,1,frames);end% zero forcing appendix[m,n,o] = size(data);n = m + 1:m + zf;data(n,:,1:o) = 0;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% BODY END %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%if ech	str1 = num2str(frames);	str2 = num2str(fr_length);	str3 = num2str(zf);		disp(' ');	disp([tag,'Pattern ',mode,' -> ',str1,' frame(s) by ',str2,...    ' symbols; ',str3,' zeros appended.']);	disp(' ');end