how to use matrix pencil or prony in matlab

Hello,

I have a distorted frequency data with respect to time in an excel file. I can graph it out in Matlab.

Since it is distorted frequency, I want to find how many external frequencies are combined with the fundamental frequency of 50Hz. After that I want to find the damping value with respect to frequency.

I want to use Matrix Pencil or Prony's method to solve this problem but I don't know where to start. Can someone guide me?