** MATLAB HELP**

I have been given a large data set in excel in a format that can be imported into matlab which i have done. The data recored is Wind Data. The point at which data is collected has been collated as "Timestamps" and they are in milliseconds. I am being asked to plot windspeed against time/date. But i need to convert the millisecond data into a usable time/date vector.

Any code help for this problem would be great.

TIA Jim.