Saving Raw IQ data in file type .dat

Hi guys,

how do I save in matlab data in file type .dat?

I have a file and it's type dat, it has RAW IQ SAMPLES so I open it in matlab, but in matlab command I write specific delimiters of my data and I want to store them (the specified data) in other file type .dat .

I mean by an example:

I have wrote a function called loadFile:

function y = loadFile(filename)
%  y = loadFile(filename)
%
% reads  complex samples from the rtlsdr file
%
fid = fopen(filename,'rb');
y = fread(fid,'uint8=>double');
y = y-127;
y = y(1:2:end) + i*y(2:2:end);

so once I load my file by writting in command window in matlab:

>>y=loadFile('frequency.dat'); %file name is frequency.

so after I have the data loaded from file name frequency.dat I want to save just y(2:6000) in another file file type .dat , how can I save the data of y(2:6000) in another file type .dat?

lets assume that y(2:6000) is stored in variable x, so

>>  x=y(2:6000) ;

how can I save in matlab the data of x (specified data of y from 2 to 6000 y(2:6000)) in another file type .dat? thanks alot!

[Image Analyst]

You forgot to attach 'frequency.dat'.

Why not just do

fid = fopen(filename,'rb');
fwrite('%f', y(2:6000));
fclose(fid);

or something like that.

Answer 1

[yuval]

There are several answers on how to save to a .dat file, for example:

https://www.mathworks.com/matlabcentral/answers/24852-save-signal-as-dat-file

Answer 2

[Walter Roberson]

Assuming it has to be written in the same order, and as integer data:

sel_y = reshape(y(2:6000), 1, []);  %row vector
sel_iq = reshape([real(sel_y); imag(sel_y)], 1, []);

fid = fopen('newfile.dat', 'w');
fwrite(fid, sel_iq, 'int8');
fclose(fid)

Note:

y = y-127;

usually if you have uint8 data, you would be subtracting 128 rather than 127. The range of int8 is -128 to +127. If your input was +255 and you subtracted 127 you would get +128 which would be out of range for int8 .