Mono-component AM-FM signal decomposition using SRF-PLL

An AM-FM signal decomposition method based on synchronous reference frame phase locked loop (SRF-PLL) is presented. This procedure estimates instantaneous amplitude (IA) and instantaneous frequency (IF) using second order generalized integrator (SOGI) and a PLL. Assuming if the synchronous reference frame is rotating at an angular velocity equivalent to the frequency of the input signal, then the IA can be obtained from the direct-axis component of the SRF, and IF from the PLL. Simulation results obtained from this method prove that SOGI with SRF PLL can successfully and accurately extract the frequency and amplitude information from the input signal for a certain range. The algorithm is tested for the sinusoidal model of AM-FM, synthetic and real speech signals.