Doppler velocity measurement using closed-loop Goertzel algorithm in PLL technique

A closed-loop comb-Goertzel algorithm in phase-locked loop technique is proposed for non-contact method of Doppler velocity extraction from a moving object. The Goetrzel algorithm is an efficient Discrete Fourier Transform (DFT) where the system complexity reduces from normal Sliding-DFT (SDFT) algorithm by inserting zero/pole in the system function. Stability is improved by introducing a damping factor that allows the system poles to lie within the unit circle z-plane. The algorithm is implemented in phase locking design to enhance the sampling control adaptively. The simulation and experimental investigations show less errors even in large noise condition.