An improved Viterbi algorithm for IF extraction of multicomponent signals

Viterbi algorithm (VA) applied to time–frequency (TF) representation is a highly performed instantaneous frequency (IF) estimator for discrete-time signals, but it suffers from switch problem (SP) at the intersected points of multicomponents on TF plane. To suppress the SP in VA, an improved VA (IVA) presented in this paper assumes that the IF variation trends between two adjacent IF variation are not large, and then, a novel penalty function is introduced and added to the original VA. To verify the algorithm, the proposed algorithm applied to several multicomponent signals is firstly simulated; then, how parameter in the new penalty function influences the performance is analyzed. Comparison of the proposed algorithm with VA on signals in the background of noise is also made in the next. Simulations indicate that in contrast to the original VA, the proposed IVA can effectively suppress the SP caused by the intersected IFs and thus can achieve more accurate IFs for the multicomponent signals especially those with monotonous IFs.