Amplitude-phase-locked-loop design using MWL criterion

A new amplitude-phase-locked-loop (AmpPLL) is introduced, using a criterion called maximum windowed likelihood (MWL). Considering an amplitude modulated/frequency modulated (AM/FM) signal in presence of the zero-mean additive white Gaussian noise (AWGN), MWL criterion is applied to track the amplitude and the frequency of the signal at the same time. The proposed AmpPLL consists of LTI filters, VCO, mixers and integrators, where the LTI filters are directly defined by the introduced window function. The proposed AmpPLL can be extended to demodulate jointly parameters of an incoming signal with more than one AM/FM component. Simulations show that the proposed AmpPLL is fast in tracking and has a small acquisition time. The proposed AmpPLL is also robust against the variations of the signal power and its phase. These characteristics suit the AmpPLL well for a wide range of applications where there is fading and jitter together.