Harminv

Harminv is a program (and accompanying library) to solve the problem of harmonic inversion. Given a discrete-time, finite-length signal that consists of a sum of finitely-many sinusoids (possibly exponentially decaying) in a given bandwidth, it determines the frequencies, decay constants, amplitudes, and phases of those sinusoids.

Harminv can, in principle, provide much better accuracy than straightforwardly extracting FFT peaks because it assumes a specific form for the signal. (Fourier transforms, in contrast, attempt to represent any data as a sum of sinusoidal components.) It is also often more robust than directly least-squares fitting the data (which can have problematic convergence). Harminv employs the “filter diagonalization method” (FDM) of Mandelshtam and Taylor.

 2007–2009 Alexey Beshenov.
Contact: al@cadadr.org.