Thread Subject: Plotting periodical measurement data with jitter to matlab

Hi,

I'm taking (periodical) voltage data with data acquisition board. I would want to postprocess the data in a manner that I would recognize what is time of each period, and make a plot which plots measurement confidence interval lines, lets say 95%.

How to recognize period, if it is more complex than combination of sine waves?
Is there any available solutions/codes for these kind of problems ?

Thanks already for answers,

-Juho