A system and method for non-invasive measurement of physical parameters of fluids in process pipes includes exciting the process pipe, measuring a vibration signal, and reducing the frequency range of the measured vibration signal to a range where a predicted resonant frequency is located. The method further comprises estimating the number of parameters and values for the parameters for a fitting algorithm, fitting the fitting algorithm to the processed measured vibration signal, and adapting the parameters so that the curve of the fitting algorithm fits to a curve of the processed measured vibration signal. The physical parameter is determined from the parameters.