A fluid flow meter system comprising: a sensor, secured to a structure defining a lumen, the sensor including: (i) a first transducer configured to transmit consecutively a plurality of copies of an ultrasonic transmit signal through a fluid flowing through the lumen; (ii) a second transducer to receive a plurality of ultrasonic signals corresponding to the plurality of transmitted copies of the ultrasonic TX signal, an analog-to-digital converter configured to sample, at a first frequency, the plurality of ultrasonic RX signals received by the second transducer, the plurality of copies of the ultrasonic TX signal transmitted with distinct time delays with respect to periods of a clock signal of the analog-to-digital converter; and a processor configured to: generate a fine resolution signal using sampled versions of the plurality of ultrasonic RX signals generated by the analog-to-digital converter, the fine resolution signal associated with a second sampling rate higher than the first sampling rate; compute a cross-correlation signal indicative of cross-correlation between the fine resolution signal and a reference waveform; and determine an estimate of a fluid flow parameter of the fluid based on the computed cross-correlation signal. a sensor, secured to a structure defining a lumen, the sensor including: (i) a first transducer configured to transmit consecutively a plurality of copies of an ultrasonic transmit signal through a fluid flowing through the lumen; (ii) a second transducer to receive a plurality of ultrasonic signals corresponding to the plurality of transmitted copies of the ultrasonic TX signal, an analog-to-digital converter configured to sample, at a first frequency, the plurality of ultrasonic RX signals received by the second transducer, the plurality of copies of the ultrasonic TX signal transmitted with distinct time delays with respect to periods of a clock signal of the analog-to-digital converter; and (i) a first transducer configured to transmit consecutively a plurality of copies of an ultrasonic transmit signal through a fluid flowing through the lumen; (ii) a second transducer to receive a plurality of ultrasonic signals corresponding to the plurality of transmitted copies of the ultrasonic TX signal, an analog-to-digital converter configured to sample, at a first frequency, the plurality of ultrasonic RX signals received by the second transducer, the plurality of copies of the ultrasonic TX signal transmitted with distinct time delays with respect to periods of a clock signal of the analog-to-digital converter; and a processor configured to: generate a fine resolution signal using sampled versions of the plurality of ultrasonic RX signals generated by the analog-to-digital converter, the fine resolution signal associated with a second sampling rate higher than the first sampling rate; compute a cross-correlation signal indicative of cross-correlation between the fine resolution signal and a reference waveform; and determine an estimate of a fluid flow parameter of the fluid based on the computed cross-correlation signal. generate a fine resolution signal using sampled versions of the plurality of ultrasonic RX signals generated by the analog-to-digital converter, the fine resolution signal associated with a second sampling rate higher than the first sampling rate; compute a cross-correlation signal indicative of cross-correlation between the fine resolution signal and a reference waveform; and determine an estimate of a fluid flow parameter of the fluid based on the computed cross-correlation signal.