function sig_modul = modul(data,md,varargin)%MODUL Multidimensional digital modulator%   S = MODUL(Q,MD,'PropertyName',PropertyValue,...) performs linear%   memoryless digital modulation of channel symbols q. The output%   signal sampled Ns-times per symbol period is assumed to be a %   complex envelope of the real bandpass signal. MD corresponds to the%   number of constellation signals. Possible values for MD are 4|8|16 %   which corresponds to 4PSK, 8PASK and 16QAM constellations%   respectively.%%   Modul Property List%%   SymbolSamples  value%   SamplePeriod   value [s]%   Gain           value%   Pulse          vector%   Echo           'on' | {'off'}%%   NOTE: The order of the 16QAM constellation signals is defined via%         external file qam16.txt and may be arbitrarily modified.%%   See also MAKEPULSE, SCALE.%   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 ECHO SYMB_SAMPLES SMPLPER GAIN PULSEname = 'MODUL';[idt,tag] = iecho(name);nopts = length(varargin) / 2;opts = reshape(varargin,[2 nopts])';ord1 = strmatch('Echo',opts(:,1));ord2 = strmatch('SymbolSamples',opts(:,1));ord3 = strmatch('SamplePeriod',opts(:,1));ord4 = strmatch('Gain',opts(:,1));ord5 = strmatch('Pulse',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% SymbolSamplesif ~isempty(ord2) % first check whether local option exists	samples = opts{ord2,2};else	if ~isempty(SYMB_SAMPLES) % than check whether global option exists		samples = SYMB_SAMPLES;	else % if there are no settings use the defaults		samples = 4; % default value	endend% SamplePeriodif ~isempty(ord3) % first check whether local option exists	smplper = opts{ord3,2};else	if ~isempty(SMPLPER) % than check whether global option exists		smplper = SMPLPER;	else % if there are no settings use the defaults		smplper = 1; % default value	endend% Gainif ~isempty(ord4) % first check whether local option exists	gain = opts{ord4,2};else	if ~isempty(GAIN) % than check whether global option exists		gain = GAIN;	else % if there are no settings use the defaults		gain = 1; % default value	endend% Pulseif ~isempty(ord5) % first check whether local option exists	pulse = opts{ord5,2};else	if ~isempty(PULSE) % than check whether global option exists		pulse = PULSE;	else % if there are no settings use the defaults		pulse = 1; % default value	endend%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% BODY BEGIN %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 16QAM definitionload qam16.txt;[frame_length,space_dim,frames]=size(data);for k = 1:frames	switch md	case 16         % 16QAM		for l = 1:space_dim		k1(:,l) = qam16(data(:,l,k) + 1,1);		k2(:,l) = qam16(data(:,l,k) + 1,2);		end				q(:,:,k) = (2 * k1 - md - 1) - i * (2 * k2 - md - 1);			otherwise		expr = 2 * pi * i / md;		q(:,:,k) = exp(expr * data(:,:,k));	end		sig_up(:,:,k) = upsample(q(:,:,k),samples);		% to compute convolution signals must be vectors -> for loop	for j = 1:space_dim		sig_modul(:,j,k) = gain * conv(pulse,sig_up(:,j,k));	endend%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% BODY END %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%if ech	[m,foo1,foo2] = size(sig_modul);	str2 = num2str(frame_length);	str3 = num2str(frames);	str4 = num2str(m);	str5 = num2str(md);		switch md	case 4		str1 = '4PSK';	case 8		str1 = '8PSK';	case 16		str1 = '16QAM';	end		disp(' ');	disp([tag,'Modulation ',str1,' performed; ',str2,' symbols,',...    str3,' frame(s).']);	disp([idt,'Total signal length: ',str4,' samples.']);	disp(' ');end