Hello Charles,
t = linspace(firstValue, finalValue, numPoints);
What really matters is to match the time vector up with when the data is collected. So if you have the data collected at 10 Hz, does it start collecting at t = 0, or t = 0.1? If you know this, you can still work out the colon notation:
nPts = numel(P);
tStart = 0; % Or 0.1
tGap = 0.1;
t = tStart:tGap:(nPts-1)*tGap+tStart;
However, you are very likely to run into floating point arithmetic issues if you do it that way, so using linspace is likely to be the better bet. Or manually specifying the end point with colon notation (which would be either 299.9 or 300 in this case). With linspace, it's probably either:
t = linspace(0, 299.9, 3000);
or
t = linspace(0.1, 300, 3000);
The reason you were seeing a vector of 30,000 points instead of 3000 is because you were using the period (0.1) as the gap, but using the number of points (3000) as the end time. Instead, it makes sense to use either all time values (0.1 and 300) or all index values if time doesn't really matter (1 and 3000).
Hope that helps!
-Cam
