Abstract

An ultrasound system steps focus and power through a series of focal zones to provide real-time seamless images with a range exceeding the depth of field of the employed ultrasound transducer. The information required for the focus and power functions are stored in memories which are read out by a zone sequencer. The data is stored in registers in the drive circuitry so that no time is lost in generating succeeding power bursts. Echoes are received from successive zones at a given steering position rather than at successive steering positions of a given zone. Provision is also made for adapting time-varying gain functions applied at a receiver as a function of zone to optimize contrast uniformity and minimize contrast discontinuities. The zone sequencer controls the input of processed echo signals into a video buffer, gating out unwanted information and splicing echo signal segments from successive zones into continuous sector lines for display on a monitor. Echoes are gathered from all zones at each steering position rather than at all steering positions for each zone so as to minimize temporal discontinuities in the constructed image.

Other References

• "Quadrature Sampling For Phased Array Application", by J. E. Powers, D. J. Phillips, M. Brandestini, R. Ferrara, and D. W. Baker, Center for Bioengineering, University of Washington, Seattle Washington (date unknown