A system for monitoring health of a rotor is presented. The system includes a processing subsystem that generates a measurement matrix based upon a plurality of resonant-frequency first delta times of arrival vectors corresponding to a blade and a first sensing device, and a plurality of resonant-frequency second delta times of arrival vectors corresponding to the blade and a second sensing device, generates a resonant matrix based upon the measurement matrix such that entries in the resonant matrix are substantially linearly uncorrelated and linearly independent, and generates a resonance signal using a first subset of the entries of the resonant matrix, wherein the resonance signal substantially comprises common observations and components of the plurality of resonant-frequency first delta times of arrival vectors and the plurality of resonant-frequency second delta times of arrival vectors.