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%RDDATATX This Script reads in the data to transmit. It is used by 
%	both the transmit and receive scripts. The transmitter script 
%	runs this script to find what data to transmit. the receiver 
%	runs this script so that it can compare the received data 
%	with the transmitted data, allowing detection of errors. 
 
%	12/8/97 Initial write up (Appears to work) 
%	genrand.m 
%	rdimage.m 
%	convbase.m 
 
%===================== 
%Read Data to transmit 
%===================== 
if DataType == 1, 
	%Use random data. 
	DataIn = genrand(1,OutWordSize,NoRandData,RandSeed); 
	disp(['Transmitting : ', num2str(NoRandData),' Random data words']); 
 
	%Data format structure. This is passed to the receiver in a file 
	%as it critical for reconstructing the data. This is needed as there 
	%is no datalink layer in the COFDM transmission. 
	%For Sending random data and a general binary file the data is sent 
	%as a serial byte stream, thus the DataHeight is 1 and the DataWidth is 
	%equal to the number of bytes sent. 
	h = 1;			%Height of the data structure (in bytes) 
	w = NoRandData;	%Width of the data structure (in bytes) 
 
elseif DataType == 2, 
	%Transmit a grey scale bitmap image. 
	[DataIn,h,w] = rdimage(infile,PictureComp); 
	disp(['Image Dimensions are : ',num2str(h),'x',num2str(w)]); 
 
	%For a grey scale bmp image the shape of the image set the data height 
	%and width 
 
	if OutWordSize ~= 8, 
		disp('Warning, OutWordSize is not 8 bit thus the image wont be decoded properly'); 
	end 
elseif DataType == 3, 
	%Transmit a general binary file 
	fid = fopen(infile,'r'); 
	if fid ~= -1, 
		DataIn = fread(fid)'; 
	else 
		error('Error opening the input data file, check file name'); 
	end 
	fclose(fid); 
	%For Sending a general binary file the data is sent as a serial byte stream, 
	%thus the DataHeight is 1 and the DataWidth is equal to the number of bytes 
	%sent. 
	h = 1;			%Height of the data structure (in bytes) 
	w = length(DataIn);	%Width of the data structure (in bytes) 
	if OutWordSize ~= 8, 
		disp('Warning, OutWordSize is not 8 bit thus the image wont be decoded properly'); 
	end 
 
elseif DataType == 4, 
	%Transmit a windows 3.1 .WAV file 
	[DataIn fs Nbits] = wavread(infile); 
	if Nbits == 8 
		DataIn = round((DataIn*128+128).'); 
	else 
		DataIn = round(DataIn.'*32768); 
	end 
 
	%DataIn = DataIn'; 
	h = 1; 
	w = length(DataIn); 
else 
	error('DataType is not valid, it must be from 1-4'); 
end 
%Convert from the data from the normal wordsize (typically 8bits) to the wordsize 
%used for transmission (typically 2bits for QPSK) 
Datatx = convbase(DataIn,OutWordSize,wordsize);