function varargout = sampling(varargin)
% SAMPLING Application M-file for sampling.fig
%    FIG = SAMPLING launch sampling GUI.
%    SAMPLING('callback_name', ...) invoke the named callback.

% Last Modified by GUIDE v2.0 12-May-2004 04:40:58

if nargin == 0  % LAUNCH GUI

	fig = openfig(mfilename,'new');

	% Use system color scheme for figure:
	set(fig,'Color',get(0,'defaultUicontrolBackgroundColor'));
    set(fig, 'Name', 'Sampling Demonstration');

	% Generate a structure of handles to pass to callbacks, and store it. 
	handles = guihandles(fig);
	guidata(fig, handles);
    
    runinter(handles);

	if nargout > 0
		varargout{1} = fig;
	end

elseif ischar(varargin{1}) % INVOKE NAMED SUBFUNCTION OR CALLBACK

	try
		[varargout{1:nargout}] = feval(varargin{:}); % FEVAL switchyard
	catch
		disp(lasterr);
	end

end

% --------------------------------------------------------------------
function varargout = Interpol_Callback(h, eventdata, handles, varargin)
% Stub for Callback of the uicontrol handles.Interpol.
%disp('Interpol Callback not implemented yet.')

runinter(handles);

% --------------------------------------------------------------------
function varargout = editN_Callback(h, eventdata, handles, varargin)
% Stub for Callback of the uicontrol handles.editN.
%disp('editN Callback not implemented yet.')

runinter(handles);

% --------------------------------------------------------------------
function varargout = pushbutton1_Callback(h, eventdata, handles, varargin)
% Stub for Callback of the uicontrol handles.pushbutton1.
%disp('pushbutton1 Callback not implemented yet.')

runinter(handles);

function runinter(handles)

m = 2^11;
x = m*real(ifft([randn(1, 20), zeros(1, m - 20)]));


N = str2num(get(handles.editN, 'String'));         % The sampling rate

meth = get(handles.Interpol, 'Value');

switch get(handles.Interpol, 'Value')   
    case {1, 3}
        h = [zeros(1, 10*N), ones(1, N)];
    case 4
        h = [zeros(1, 10*N-N+1), [1:N, N-1:-1:0]/N];
    case 2
        h = sin(pi*(-10*N:10*N)/N+1e-9)./(pi.*(-10*N:10*N)/N+1e-9);
    otherwise
        disp('Wrong option')
end

ii = floor(N/2):N:m;

set(handles.axesdata, 'Nextplot', 'Replace')
plot(1:m, x, 'Parent', handles.axesdata);
set(handles.axesdata, 'Xlim', [0, m]);

set(handles.axesdata, 'Nextplot', 'Add');
plot(ii, x(ii), 'or', 'Parent', handles.axesdata);

x1 = zeros(size(x));
x1(ii) = x(ii);
x2 = conv(h, x1);
xi = x2((10*N+1):(10*N+m));

plot(1:m, xi, 'r', 'Parent', handles.axesdata)

set(handles.axeserr, 'Nextplot', 'Replace')
plot(1:m, xi - x, 'Parent', handles.axeserr)
set(handles.axeserr, 'Xlim', [0, m]);
%set(handles.axeserr, 'Nextplot', 'Add')
%plot(ii, zeros(size(ii)), 'or', 'Parent', handles.axeserr)

set(handles.axeserr, 'Ylim', get(handles.axesdata, 'Ylim'));

%plot(1:m, xi, 1:m, x, ii, x(ii), 'o')