In a previous paper, the author presented a Fourier-based algorithm for monitoring the characteristics of the damped oscillating "modes" which are set up after a disturbance in an electric power-distribution system. This earlier paper permitted the analysis of multiple modes but only if the modes were sufficiently well separated to be resolved with conventional Fourier techniques. This current paper extends the previous work to enable the processing of multiple modes which are very closely spaced in frequency. Importantly, the proposed algorithm has good noise performance. A theoretical justification for the new method is presented, and simulations are provided to confirm the theory. The scheme is also tested on a real power-system example.