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超声发射脉冲和反射波在人体组织中传播时的衰减,受查组织的特性不明和结构的运动,以及超声束方向的经常变化等,所有这些因素决定了用常规的超声放大器难以得到满意的图象。现在,在超声放大器中多采用适当的增益控制技术,以尽量补偿声能衰减和适应于对各种复杂结构的探查,这在希望显示组织界面的场合是十分重要的。本文介绍一种我国近几年出现的新型器件——双栅MOS场效应管(简称双栅管)在诊断超声增益控制方面的应用。
The attenuation of the transmitted and reflected waves of ultrasound in human tissue, the unknown characteristics of the examined tissue and the movement of the structure, as well as the regular changes in the direction of the ultrasound beam, all of these factors determine the difficulty of obtaining satisfactory images with conventional ultrasound amplifiers Like At present, the use of appropriate gain control techniques in ultrasonic amplifiers to try to compensate for sound energy attenuation and to adapt to the exploration of various complex structures, which in the hope of showing the organizational interface is very important occasion. This article describes a new device in China in recent years - dual gate MOS FET (double gate) in the diagnosis of ultrasonic gain control applications.