A method to control an ultrasonic flowmeter, the ultrasonic flowmeter including a pipe segment; a first pair of transducers defining a first ultrasonic path; and a second pair of transducers defining a second ultrasonic path is provided. The method includes: a) transmitting a first code along the first ultrasonic path; b) simultaneously transmitting a second code along the second ultrasonic path, wherein the first and second code are non-correlated; c) receiving a first ultrasonic signal by the first pair of transducers; d) receiving a second ultrasonic signal by the second pair of transducers; e) correlating the transmitted first code with the first ultrasonic signal; and f) correlating the transmitted second code with the second ultrasonic signal.