Acoustic Patents (Class 702/48)
  • Patent number: 6539316
    Abstract: A method for detecting a phase difference between first and second input signals is provided. The method includes modulating a duty cycle of first and second intermediate signals from a first duty cycle based on the phase difference between the first and second input signals. The method further includes creating a differential output signal based on the modulated duty cycles of the first and second intermediate signals that is related to the phase difference between the first and second input signals.
    Type: Grant
    Filed: January 6, 2000
    Date of Patent: March 25, 2003
    Assignee: Data Sciences International, Inc.
    Inventors: Gregory P. Doten, Ronald E. Patton
  • Patent number: 6535835
    Abstract: The volume of fluid flow within a vessel (VE) is measured by an ultrasound system. Ultrasound waves backscattered from the fluid within the vessel generate data from which velocity values representing components of velocity (Vx and Vy) of the fluid flow in the scan plane (IP) are calculated. Grayscale data is correlated and the rate of decorrelation (D) of the data is calculated. The volume flow of the fluid (F) is estimated in response to the velocity signals and the rate of decorrelation (D).
    Type: Grant
    Filed: January 31, 2000
    Date of Patent: March 18, 2003
    Assignees: GE Medical Systems Global Technology Company, LLC, The Regents of the University of Michigan
    Inventors: Jonathan M. Rubin, Jeffrey Brian Fowlkes, Theresa Ann Tuthill, Anne Lindsey Hall
  • Patent number: 6360175
    Abstract: A drive system is taught for controlling the modal content of any number of drive signals used to excite any number of drives on a vibrating conduit such as is found in a Coriolis mass flowmeter or a vibrating tube densimeter. One or more motion signals are obtained from one or more spatially distinct feedback sensors. The motion signals are preferably filtered using a multi-channel modal filter to decompose the motion signals, each of which contain modal content at a plurality of vibration modes, into n single degree of freedom modal response signals. Each modal response signal corresponds to one of the vibration modes at which the vibrating conduit is excited. The n modal response signals are input to a drive channel having a separate processing channel for each of the n modal response signals.
    Type: Grant
    Filed: February 25, 1998
    Date of Patent: March 19, 2002
    Assignee: Micro Motion, Inc.
    Inventors: Timothy J. Cunningham, Stuart J. Shelley
  • Publication number: 20010010031
    Abstract: A flow rate measuring apparatus capable of accurately measuring a flow rate of fluctuating fluid. A mode setting circuit selectively sets any one of a plurality of predetermined transmission modes different in transmission timing. The mode setting circuit sets any one of a first transmission mode which permits an ultrasonic wave to be transmitted at a predetermined timing for every period of a flow waveform of exhaust gas, a second transmission mode which permits an ultrasonic wave to be transmitted at a timing shifted by a predetermined time for every period of the flow waveform of the exhaust gas and a third transmission mode which permits an ultrasonic wave to be transmitted at predetermined intervals.
    Type: Application
    Filed: January 24, 2001
    Publication date: July 26, 2001
    Applicant: NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGY
    Inventors: Masaki Takamoto, Akira Yamasaki, Kenzo Hosoi, Satoshi Arai, Kazuyoshi Shimizu
  • Patent number: 6226598
    Abstract: Measuring the propagation time of a sound signal between two spaced-apart transducers disposed in a fluid flow involves determining the zero-crossing of the signal. Each received sound signal is sampled and digitized, then for each period of the sampled and digitized signal the maximum amplitudes P− and P+ of the two lobes of the period under examination are determined. The ratio of the amplitudes are compared to an ideal amplitude ratio between the maximum amplitudes Pi− and Pi+ of two lobes of a first ideal characteristic period. The first zero-crossing of the characteristic oscillations of the signal is determined. And, as a function of the result of the comparison relative to a threshold value Gs, the period under examination is accepted or ignored as a characteristic period. The zero-crossing thereof is determined or not determined between the two lobes of the characteristic period.
    Type: Grant
    Filed: December 4, 1998
    Date of Patent: May 1, 2001
    Assignee: Schlumberger Industries, S.A.
    Inventors: Robert De Vanssay, Jérôme Juillard
  • Patent number: 6151558
    Abstract: Methods, devices and system for measuring the speed of the watercraft relative to the water through which it travels. An embodiment comprises two streamlined fins configured to extend at least partially below the waterline. The fins are oriented parallel to the water flow so that as the watercraft moves, the water flows in between the fins in a smooth unobstructed motion. One piezoelectric transducer is mounted in each fin so that the acoustic signal path between the transducers is a straight line. The transducers are offset upstream and downstream so that water flow between the fins can significantly affect the acoustic signal travel time between the upstream and downstream sensors.
    Type: Grant
    Filed: February 10, 1998
    Date of Patent: November 21, 2000
    Inventors: James R Conant, Szeeming Yao
  • Patent number: 6119070
    Abstract: 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.
    Type: Grant
    Filed: March 23, 1998
    Date of Patent: September 12, 2000
    Assignee: Schlumberger Industries, S.A.
    Inventors: Lionel Beneteau, Benoit Froelich
  • Patent number: 5835884
    Abstract: A method of determining a characteristic of a fluid involves measuring a sonic transit time (102), along a non-perpendicular path, through the fluid. The sonic transit time is used to determine a speed of sound in the fluid (104). A measured flow rate (106) is determined from the sonic transit time. A friction factor (108) is calculated using the speed of sound and the measured flow rate. Next, a velocity profile (110) is determined using the friction factor. Finally, an adjusted flow rate is calculated (112) using the velocity profile.
    Type: Grant
    Filed: October 4, 1996
    Date of Patent: November 10, 1998
    Inventor: Alvin E. Brown