Acuson Corporation

California Institute of Technology

Ian A Galton

Samuel H Maslak

Paul E Chandler

Hugh G Larsen

Joel S Chaffin

Mehebub S Karmali

An acoustic scanning method and apparatus implemented by transmitting ultrasonic pressure waves and receiving return echoes on a set of spatially non-overlapping acoustic lines scanned along a transducer array with the active acoustic lines shifted and steered so that each acoustic line originates at an arbitrary point on and at an arbitrary angle to the face of the array. In a preferred embodiment, an extension of each acoustic line may also pass through a substantially common vertex that is not on the face of the transducer array, but preferably behind it a selectable distance to provide an extended field of view. The extended field-of-view is defined by the selectively variable location of the common vertex of the acoustic lines and the physical ends of the array, may use the entire transducer array in the near-field, has high quality resolution in both near and far fields, and may simultaneously transmit and receive two or more ultrasound beams from the same transducer aperture.

Variable origin-variable acoustic scanning method and apparatus

An acoustic scanning method and apparatus implemented by transmitting ultrasonic pressure waves and receiving return echoes on a set of spatially non-overlapping acoustic lines scanned along a curved linear transducer array with the active acoustic lines shifted and steered so that each acoustic line originates at an arbitrary point on and at an arbitrary angle to the face of the array. In a preferred embodiment, an extension of each acoustic line may also pass through a substantially common vertex that is a selectable distance behind the array to provide a field-of-view defined by the selectively variable location of the common vertex and the physical ends of the array, may use the entire transducer array in the near-field, has high quality resolution in both near and far fields, and may simultaneously transmit and receive two or more ultrasound beams from the same transducer aperture.

Variable origin-variable angle acoustic scanning method and apparatus

An approach is presented for relaxing the oversampling requirements in a .DELTA..SIGMA. modulator based analog-to-digital converter through parallel .DELTA..SIGMA. modulation channels with decimation filtering and modulation by sequences u.sub.r (n) and v.sub.r (n) derived, for example, from an M.times.M Hadamard matrix. By combining M .DELTA..SIGMA. modulators, each with an oversampling ratio of N, an effective oversampling ratio of approximately NM is achieved with only an M-fold increase in the quantization noise power. In the special case of N=1, full-rate analog-to-digital conversion is achieved. The individual .DELTA..SIGMA. modulators can be any selected from a large class of popular .DELTA..SIGMA. modulators. Unlike most other approaches to trading modulator complexity for accuracy, the system retains the robustness of the individual .DELTA..SIGMA. modulators to circuit imperfections.

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Pasadena, CA, United States of America

Ian A Galton