Pre-filtered Phase-Locking Scheme for Multi-component AM–FM Signal Decomposition

Abstract

An online multi-component AM–FM signal decomposition method is proposed based on pre-filtered phase-locking scheme. A second-order generalized integrator (SOGI) and cascaded delayed signal cancelation technique (CDSC) are employed as pre-filters for the phase-locking scheme (PLL). The CDSC technique separates the AM–FM signals from the multi-component signal as a mono-component AM–FM, and a PLL structure demodulates the instantaneous amplitude (IA) and instantaneous frequency (IF) from the individual AM–FM signals. The IF estimated from PLL is fed back to SOGI and CDSC blocks in order to adaptively adjust the number of samples. PLL structures are augmented in parallel to extract IA and IF of multi-component AM–FM signals. The proposed scheme is implemented in field programmable gate array and tested for sinusoidal multi-component AM–FM model. It is evident from the simulation and experimental investigation that the algorithm could efficiently track IF and IA and offers good dynamic response and operating range.