Time-frequency analysis is naturally the way of characterization of non-stationary signals. One fundamental parameter of the any-non-stationary is the Instantaneous Frequency Law of its components. The Instantaneous Frequency Law (IFL) estimation is usually subject of tracking in time-frequency domain, especially in the case of complex time-frequency structures. Using the concept of phase diagram representation of a signal, related to the concept of nonlinear dynamic systems, we aim to track the Instantaneous Frequency Law of a received signal, providing a new method for the estimation of the frequency's evolution in time. The main advantage of this approach is the capability of phase diagram representation to highlight the signal's phase continuity, very useful for an accurate IFL tracking.