Phase-strip sequence estimation: A phase unwrapping/Tracking algorithm

This paper presents a simple phase tracking and demodulation algorithm which uses a state model of the phase process to unwrap and track noisy phase measurements. The wrapped phase measurements are compared with the predictions of three Kalman filters to obtain distance metrics for Viterbi decoding of a trinary unwrapping symbol sequence. The algorithm is used to demodulate an FM signal and the results are compared with those of a first order PLL and the MAP frequency estimation technique of Tufts and Francis [3].