How to find the period of the attached signal in simulink?

Hallo everyone, i would like to find the period of a signal whose the frequency changes over the time. I have an idea how to do it. By measuring the time corresponding to two consecutives peaks values of the signal. the difference of the both times correspond to the period. I want to implement it in Simulink, not in Matlab. i dont know which block i should use. any idea??i have attached above one example of a signal whose the frequency changes over time.

Thanks in Advance