1. A continuous phase modulation detector comprising: receiver means having a trellis structure and being adapted for receiving digitally modulated signals having a generally continuous phase; observation means adapted for performing multi-symbol observations on received digitally modulated signals; memory means adapted for storing historic observation data corresponding to multi-symbol observations performed by the observation means; adjustment means adapted for selectively adjusting the observation means in accordance with the stored historic observation data; cumulative means adapted for acquiring cumulative observation data by recursively computing observation data corresponding to multi-symbol observations performed by the observation means; wherein the memory means is adapted for storing cumulative observation data corresponding to multi-symbol observations performed by the observation means, in a traceback matrix; evaluating means adapted for evaluating the cumulative observation data stored in the traceback matrix; and decision means adapted for making a decision on a status of the trellis-based lock detector by selecting from the group consisting of: a lock status, and unlock status, based on the evaluation of acquired cumulative observation data.