creating a plot of one cycle from multipel cycles

"I'm working on analyzing engine data, and I'm interested in computing the average plot of a cycle using the median method. Could anyone guide me on how to accomplish this?

Specifically, I have data collected over multiple engine cycles, and I'm considering using the median to compute the average behavior of the engine. However, I'm unsure about the process of averaging the median values across cycles.

I'm thinking of taking the median for each cycle and then averaging the medians for the first data point of each cycle, the second data point of each cycle, and so on. Is this the correct approach? If not, could someone suggest the correct method for computing the average cycle plot using the median?

Any insights or suggestions would be greatly appreciated. Thank you!"

Answer 1

[Star Strider]

This is called an ‘ensemble average’. One approach to it (I have posted several times on these problems) is in Combining repetitive curves into one average curve, It would help to have your data, or a representative sample of it.

The essential idea is to identify one or more reference points in a signal (peaks, valleys, or some combination of them are most commonly used) and then create an appropriate window with respect to each cycle that centres on one or more of these points. After that, it is straightforward to combine them and take the means or medians and calculate other statistics, even if the signals differ in length from cycle to cycle. The calculations are all done with respect to the ‘shortest’ cycle with respect to the independent variable, usually distance or time.