Schlumberger Industries, Sa

Schlumberger Industries

Lionel Beneteau

Benoit G Froelich

Alain G Bazin

Michel Gervais

Jean Simon

Philippe Benabes

Robert De Vanssay

Jacques Oksman

Olivier Boubal

An ultrasound apparatus for measuring a fluid flow rate includes a processor which receives an analog signal from a receiver transducer then transforms it into a digitized signal used for determining the fluid flow rate. The processor includes a bandpass sigma-delta converter having a bandpass loop filter, and a digital-to-analog converter in a feedback loop.

Device and method for ultrasonic measurement of a fluid flow rate comprising a sigma-delta band pass analog-to-digital converter

A method for measuring a fluid flow rate between two points of a fluid flow according to which a measurement of the respective propagation times of two acoustic signals transmitted in opposite directions is combined with a measurement of acoustic phase shifts respectively induced in each signal. Each received signal is sampled and digitized and the corresponding acoustic phase shift is determined by synchronous detection. During successive iterations, a programmable phase shift dependent on the value of the acoustic phase shift obtained by synchronous detection in the previous iteration is determined for each iteration, so that the result of the synchronous detection step in the current iteration is as close as possible to zero, and the acoustic phase shift is therefore substantially the same as the last programmable phase shift.

Method for acoustically measuring a fluid flow rate

The invention relates to ultrasound apparatus for measuring the flow speed of a fluid, the apparatus comprising first and second ultrasound transducers disposed at points that are spaced apart in the direction of fluid flow, a transmitter module, a receiver module, and switch means organized so that each of the first and second transducers operates alternately as a transmitter and as a receiver. The transmitter module includes at least one transmission signal generator whose output is permanently connected via two logic gates each followed by a respective resistive divider bridge to a respective first terminal of the first and second transducer, and in that the first and second switch means are interposed respectively between the first terminals of said first and second transducers and the receiver module.

Ultrasound apparatus for measuring the flow speed of a fluid

A physical parameter represented by variation in time of a physical magnitude G capable of varying between a minimum value G.sub.min and a maximum value G.sub.max is determined. The physical magnitude G is measured at variable time intervals referred to as sampling times. After each measurement of the physical magnitude G, the corresponding value of the physical parameter, and also the theoretical maximum error that could have occurred in the determination of the physical parameter are determined. The sampling time prior to each new measurement of the physical magnitude G is determined in such a manner as to ensure that a predetermined error threshold E.sub.max is not exceeded while determining the value of the physical parameter corresponding to the new measurement of the physical magnitude G.

Method and apparatus for determining a physical parameter represented by

A modulated integrator circuit frequency modulates an input signal and has an integrator comprised of an amplifier (31) and an intregrating capacitor (35) connected across an input and an output of the amplifier. The circuit further comprises a storage capacitor (36) in addition to any switching capacitors (C) associated with the modulation of the input signal if present. The storage means (36) is connectable between the input and the output of the amplifier in parallel with the integrating capacitor. The storage capacitor stores a charge associated with the voltage of the output of the amplifier and transfer such charge to the integrating capacitor to enable reversal of the charge of the integrating capacitor in synchronism with the frequency modulation of the input signal.

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Montrouge, France

Lionel Beneteau