Patent ID: 6696843
Filing Date: 2004-02-24
Classification: G01F

Abstract:
Ultrasound apparatus for measuring a fluid flow rate, the apparatus comprising:first and second transducers placed in the fluid whose flow rate is to be determined, one of the transducers, also referred to as an â€œemitterâ€  transducer, operating in emission mode while the other transducer, also referred to as a â€œreceiverâ€  transducer, operates in reception mode, the emitter transducer being designed to emit an ultrasound wave into the fluid and the receiver transducer being designed to transform said ultrasound signal into an analog signal, wherein the transducers comprise respective piezoelectric plates each having two opposite surfaces, said surfaces being metallized so as to be connected to connection terminals of the transducer, one of the two terminals of each transducer being permanently connected to ground, the other terminal being connected respectively to the output of the analog-to-digital converter, to ground, and to the input of the bandpass loop filter by means of switches, processor means for processing said analog signal, the processor means being connected to the receiver transducer and being designed to transform said analog signal into a digitized signal used for determining the fluid flow rate; said analog signal processor means including a bandpass sigma-delta converter including: a bandpass loop filter whose input is connected to the output of said receiver transducer; an analog-to-digital converter whose input is connected to the output of said loop filter, the output of said analog-to-digital converter forming the digital output of said analog-to-digital converter; and a digital-to-analog converter forming a feedback loop, connecting the output of the analog-to-digital converter to the input of said loop filter.