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本文论述一种用于手动扫描医用超声成像系统的动态聚焦环阵。与一个单元的换能器相比,动态聚焦能显著地改善图象。系统中用了七个单元菲涅尔图样阵,工作于2.25兆赫或3.5兆赫。每个单元备有独立的发射器及接收器。通过操作,发射时的焦域可预先选择,而在接收时通过采用数控延迟单元可达到连续的电聚焦。采用费涅尔图样,能使各单元对超声脉冲提供大致一样的信号强
This article discusses a dynamic focus ring array for manual scanning of medical ultrasound imaging systems. Dynamic focusing can significantly improve the image compared to a single-cell transducer. Seven Fresnel patterns were used in the system, operating at 2.25 MHz or 3.5 MHz. Each unit has a separate transmitter and receiver. By operation, the focal field at the time of emission can be pre-selected, and continuous electro-focusing can be achieved by using a numerical control delay unit upon reception. The use of Fresnel patterns allows each cell to provide approximately the same signal strength to the ultrasound pulse