An acoustic Doppler system including an acoustic subsystem controller operatively connected to a plurality of acoustic transceivers, with a first of the plurality of acoustic transceivers, operating at a first acoustic frequency, operatively connected to a first group of at least one transducer, and a second of the plurality of acoustic transceivers, operating at a second acoustic frequency, operatively connected to a second group of at least one transducer, where the acoustic subsystem controller includes a digital circuit configured to sample analog signals received from the first and second groups of transducer in pairs having a pair-wise sampling frequency that is four times the operating frequency of associated acoustic transceiver.; Also presented is a method of sampling acoustic Doppler signals received from such devices, with samples comprising a pair of values taken with a pair- wise sampling frequency that is four times the operating frequency of associated acoustic transceivers, and the resulting pairs of values being further processed as representative values of the cosine and sine components of a Doppler-shift signal.