Finding center point after implementing sliding window

I have some cluster of points generated by a sliding window. There is a information signal of which I want to find the frequency of. When the sliding window passes the edge of the information signal, high frequency components show up. I wish to write a code to first detect a cluster of points and then find the center point where the main signal is. The data I have attached has 3 clusters of such points. The code should pin point only one value to each cluster. As the results are carried out in controlled manner, there values should be same or at least very close to each other as they denote a similar event.

I have attached the .txt file of the frequency signal.