Mono-component AM–FM Signal Decomposition Based on Discrete Second-Order Generalized Integrator Phase-Locked Loop

Abstract

A mono-component AM---FM signal decomposition method is proposed using discrete second-order generalized integrator and phase-locking scheme. A discrete second-order generalized integrator (SOGI) is employed in the algorithm as a quadrature signal generator for a center carrier frequency. The outputs from SOGI are in-phase and quadrature components of the AM---FM signal. These components are processed in the discrete phase-locked loop to estimate instantaneous frequency variation and instantaneous amplitude variation. The estimated instantaneous frequency variation is fed back to SOGI to adjust the center frequency. Proposed mono-component AM---FM demodulator is implemented in FPGA platform. The algorithm offers good acquisition time, accuracy, and operating range. Experimental investigations performed on the algorithm prove the efficacy and suitability of the algorithm for mono-component AM---FM demodulation.