Abstract: An ultrasonic flow meter (UFM) includes a first and second ultrasonic transducer for attaching to a pipe, and a transceiver coupled to the transducers by a multiplexer. A controller having an associated memory runs an adaptive multi-frequency hopping and coding algorithm that selects ?1 frequency to be hopped within the measured transducer impedance spectrum using a threshold level that selects at least a peak for the phase or a valley for the magnitude, and selects a coding scheme for the chosen frequency to provide a coded frequency sequence. A received signal generated responsive to an ultrasonic signal with the coded frequency sequence into the fluid is decoded, and peak detection is performed on the decoded received signal. The travel time is calculated from the decoded signal, and a speed of the fluid is then determined from the travel time.

Abstract: An ultrasonic flow meter (UFM) includes a first and second ultrasonic transducer for attaching to a pipe, and a transceiver coupled to the transducers by a multiplexer. A controller having an associated memory runs an adaptive multi-frequency hopping and coding algorithm that selects ?1 frequency to be hopped within the measured transducer impedance spectrum using a threshold level that selects at least a peak for the phase or a valley for the magnitude, and selects a coding scheme for the chosen frequency to provide a coded frequency sequence. A received signal generated responsive to an ultrasonic signal with the coded frequency sequence into the fluid is decoded, and peak detection is performed on the decoded received signal. The travel time is calculated from the decoded signal, and a speed of the fluid is then determined from the travel time.