www.pudn.com > communication-systems-using-MATLAB-m-files.rar > convnyq.m

% Convolution of Raised Cosine Pulses 
 
function convnyq(alpha,action) 
 
if nargin == 0 alpha = .5; end; 
if isstr(alpha) alpha = str2num(alpha); end; 
if (alpha>1) alpha = 1; end; 
if (alpha<0) alpha = 0; end; 
 
if (nargin<2) 
  action = 'start'; 
end; 
 
if (strcmp(action,'start') | strcmp(action,'update')) 
 
	rolloff = num2str(alpha); 
 
	aufloesung = 200; 
	laenge = 5; 
 
	x1 = linspace(-laenge,laenge,aufloesung); 
	g1 = nyqro(alpha, x1); 
 
	%convolution 
 
	c = conv(g1,g1);  
 
	rng = -2 * x1(1);       % maximum axis value 
	anz = (length(c)-1)/2;  % number of axis values for each side 
 
	c = c ./ (anz/rng);     % amplitude correction 
 
	x2 = zeros(size(c));    % compute new x coordinates 
 
	for k=1 : length(c) 
	  x2(k) = (k-anz)*rng/anz; 
	end; 
 
end; 
 
if strcmp(action,'start') 
 
	set(0,'Units','pixels'); 
	scnsize = get(0,'ScreenSize'); 
 
	% open window 
	figure ('Position', [0.25*scnsize(3)   0.15*scnsize(4)   0.7*scnsize(3)   0.7*scnsize(4)], ... 
		'Name', 'Convolution of Raised-Cosine Pulses', ... 
		'Tag', 'ConvNyquistRolloff', ... 
		'NumberTitle','off' ... 
		); 
 
	set(gcf,'DefaultTextColor','m'); 
	backcolor = get(gcf,'Color'); 
 
 
	% ----------------------------------- 
	% Slider for Rolloff Factor  
	% ----------------------------------- 
	 
	text = uicontrol(gcf, ... 
		'Tag', 'ConvNyqTextfeld', ... 
		'Style', 'text', ... 
        'Units', 'normalized', ... 
		'Position', [.01 .85 .08 .1], ... 
		'BackgroundColor', 'red', ... 
		'ForegroundColor', 'white', ... 
		'String', sprintf('Roll-off\nfactor\n%1.3f',alpha) ... 
		); 
	 
cb = 'convnyq(get(findobj(gcf,''Tag'',''ConvNyqSlider''),''Value''),''update'');'; 
 
	slider = uicontrol(gcf, ... 
		'Tag', 'ConvNyqSlider', ... 
		'Style', 'slider', ... 
        'Units', 'normalized', ... 
		'Position', [.04 .2 .02 .6], ... 
		'Min', 0, ... 
		'Max', 1, ... 
		'Value', alpha, ... 
		'Callback', cb ... 
		); 
 
 
	% --------------------------------- 
	% Plot 1: Raised Cosine Pulse 
	% --------------------------------- 
	 
	subplot(2,2,1), plot(x1,g1,'EraseMode','background') 
 
	title('Raised-Cosine Pulse')  
	xlabel('t/T') 
	ylabel('g(t/T)') 
	set(gca,'Tag','ConvNyqPlot1'); 
 
	pos1 = get(gca, 'Position'); 
	set(gca,'Position',[pos1(1)-.1/2*pos1(3)+.04 pos1(2) 1.1*pos1(3) pos1(4)]); 
	pos1 = get(gca, 'Position'); 
 
	set(gca,'YLimMode','manual'); 
	set(gca,'YLim',[-.23 1]); 
 
	set(gca,'XTick', [-5 :1: 5]); 
	grid 
 
 
	% --------------------------------- 
	% Plot 2: Raised Cosine Pulse 
	% --------------------------------- 
	 
	subplot(2,2,2), plot(x1,g1,'EraseMode','background') 
	title('Raised Cosine Pulse')  
	xlabel('t/T') 
	%ylabel('g(t/T)') 
	set(gca,'Tag','ConvNyqPlot2'); 
 
	pos2 = get(gca, 'Position'); 
	set(gca,'Position',[pos2(1)-.1/2*pos1(3)+.04 pos2(2) 1.1*pos2(3) pos2(4)]); 
	pos2 = get(gca, 'Position'); 
 
	set(gca,'YLimMode','manual'); 
	set(gca,'YLim',[-.23 1]); 
	set(gca,'XTick', -5: 1 : 5); 
	grid 
 
 
 
	% ------------------ 
	% Convolution star 
	% ------------------ 
 
	text = uicontrol(gcf, ... 
		'Style', 'text', ... 
        'Units', 'normalized', ... 
		'Position', [pos1(1)+pos1(3)+0.005, pos1(2)+pos1(4)/2-.15/2, (pos2(1)-pos1(1)-pos1(3))-0.005, .10], ... 
		'FontSize', 30, ... 
		'BackgroundColor', backcolor, ... 
		'ForegroundColor', 'm', ... 
		'String', '*' ... 
		); 
 
 
	% ---------------------------------------------------------- 
	% Plot 3: Convolution 
	% ---------------------------------------------------------- 
 
	subplot(2,2,3), plot(x2,c,'EraseMode','background') 
	title('Result of Convolution')  
	xlabel('t/T') 
	ylabel('g(t/T)') 
	set(gca,'Tag','ConvNyqProdukt'); 
 
	pos3 = get(gca, 'Position'); 
	set(gca,'Position',[pos1(1) pos3(2) pos1(3)+pos2(3)+(pos2(1)-pos1(1)-pos1(3)) pos3(4)]); 
	set(gcf,'DefaultTextColor','m'); 
 
	set(gca,'XLimMode','manual'); 
	set(gca,'XLim',[-rng rng]); 
	set(gca,'YLimMode','manual'); 
	set(gca,'YLim',[-0.23 1]); 
 
	set(gca,'XTick', -10: 1 : 10); 
	grid 
 
end; 
 
if strcmp(action, 'update') 
 
    set(0,'CurrentFigure',findobj(0,'Tag', 'ConvNyquistRolloff')); 
 
	set(findobj(gcf,'Tag','ConvNyqTextfeld'),'String', sprintf('Roll-off\nfactor\n%1.3f',alpha)); 
 
	set(get(findobj(gcf,'Tag','ConvNyqPlot1'),'Children'),'YData',g1); 
	set(get(findobj(gcf,'Tag','ConvNyqPlot2'),'Children'),'YData',g1); 
	set(get(findobj(gcf,'Tag','ConvNyqProdukt'),'Children'),'YData',c); 
 
	drawnow; 
 
end; 
 
clear action;