Extracting data points from signals

I have a matrix of size 147456 x 3, This signal represents a data of 72 seconds where the sampling frequency was 2048. The signal is basically a set of 6 repitions (12s each) and the 1st 6 sec, corresponds to activity 1 while the next six seconds corrsponds to activity 2.

Now we want to separate activity 1 and activity 2 into separate matrices.

i have wrote a code but it is not doing the job. Kindly guide me

activity1 = [ ]

for i = 6:6:66

repitition = data(i*fs+1 : (i+6)*fs, :);

activity1 = vertcat(data, repitition)

end

Answer 1

[Frank Meier]

How about this?

%Inputs
sf = 2048;
rep = 6;
time = 72;

%Matrix Init
xRows = sf * time;
xCols = 3;
x = [1:xRows;1:xRows;1:xRows]';
activity1 = zeros(xRows/2,xCols);
activity2 = zeros(xRows/2,xCols);

%Samples per repetition
spr = time*sf/rep;

% Split data
for repIndex = 0:rep-1
    for rowIndex = 1: spr /2   % 72/6*2048 /2 = 12288
        activity1(repIndex*spr/2+rowIndex , :) = x(rowIndex+repIndex*spr,:);
        activity2(repIndex*spr/2+rowIndex , :) = x(rowIndex+ spr/2 + repIndex*spr,:);
    end
end

Indices should be checked for valid integers, depends on your pre processing of sample data.