Design and Simulation of Digital Carrier Tracking Technique for High Dynamic Spread Spectrum Receiver

Abstract

In this project the digital carrier tracking technique with a structure of frequency-locked loop (FLL) assisted phase-locked loop (PLL) is designed and simulated for high Doppler conditions. The frequency and phase decision are very easy to realize by programmable digital device. Due to the frequency pulling of FLL, the pass-band of the filter in PLL can be made very narrow to suppress the noise, and the PLL can lock the phase of carrier with high accuracy. In the proposed work, the study and simulation of crossproduct auto frequency tracking (CPAFC) and four phase frequency discrimination (atan2), and the improved digital Costas loop to achieve carrier synchronization will be carried out. The performance of the improved digital Costas loop is verified by simulation and this method works well in the environment when input signal changes in a large dynamic range.
MATLAB/GNU OCTAVE simulation tool will be used for simulation. The simulation results, applications, merits and demerits of proposed approach will be analyzed and will be documented.