DESIGN AND IMPLEMENTATION OF MULTI-COMPONENT AM-FM DEMODULATOR USING DELAYED SIGNAL CANCELLATION TECHNIQUE

Abstract

An on-line multi-component AM-FM signal decomposition method is proposed based on delayed signal cancellation (DSC) technique. A second order generalized integrator (SOGI) is employed as a quadrature signal generator. Cascaded delayed signal cancel-lation (CDSC) block is incorporated in a phase locked loop (PLL) structure to estimate the mono-component AM-FM signals. CDSC block separates the AM-FM signals from the multi-component signal as a mono-component AM-FM, and a PLL structure de-modulates the instantaneous amplitude (IA) and instantaneous frequency (IF) from the individual AM-FM signals. Instantaneous frequency estimated from PLL is fed-back to SOGI and CDSC blocks in order to adaptively adjust the number of samples. PLL struc-tures consisting of CDSC blocks 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 (FPGA) and tested for sinusoidal AM-FM model of multi-component AM-FM signals. Multi-component decomposition method yields good dynamic response and operating range for instantaneous amplitude and frequency extraction. It is evident from the simulation and experimental investigation that the algorithm could efficiently track the instantaneous frequency and instantaneous amplitude of a multi-component signal. The objectives of this dissertation work include: To propose an on-line multi-component AM-FM demodulation scheme. Simulate the proposed scheme with different amplitude and frequency conditions. Implement the proposed scheme on FPGA.