If 'temp' is your array that is 48000x1 you can specify specific indices as follows:
temp(1:X, 1)
This will get rows in temp from 1 to 'X' in the first column. General form being:
temp(w:x, y:z)
This will return the values in temp from rows 'w' to 'x' and columns 'y' to 'z'.
To then plot simply:
plot(temp(1:X, 1))
Hope this helps!
//edit Just reread your question and interpreted it a completely different way. So in case the above doesn't help:
You could probably write a short little script to separate out the values of the array that are less than 'X' and plot a separate array.
Try something like this:
for i=1:length(myBigArray)
if (myBigArray(i) < 'X')
temp(i) = myBigArray(i);
end
end
plot(temp);
Not the prettiest, but I think it might do what you want. You might also find the matlab function 'find' useful for your application. This function can return the indices of your array that satisfy a condition: find(myBigArray < X)
