Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong SAR, China.
IEEE Trans Ultrason Ferroelectr Freq Control. 2012 Jul;59(7):1558-67. doi: 10.1109/TUFFC.2012.2355.
High-frequency (>20 MHz) ultrasound (HFUS) imaging systems have made it possible to image small structures with fine spatial resolution. They find a variety of biomedical applications in dermatology, ophthalmology, intravascular imaging, and small-animal imaging. One critical technical challenge of HFUS is to generate high-voltage, high-frequency pulsed signals to effectively excite the transducer for a high SNR. This paper presents the development of a multifunctional, reconfigurable pulse generator for HFUS imaging. The pulse generator can produce a high-voltage unipolar pulse, a bipolar pulse, or arbitrary pulses for B-mode imaging, Doppler measurement, and modulated excitation imaging. The characteristics of the pulses, such as timing, waveform, and frequency are reconfigurable by a high-speed field-programmable gate array (FPGA). Customized software was developed to interface with the FPGA through a USB connector for pulse selection, and easy, flexible, real-time pulse management. The hardware was implemented in a compact, printed circuit board (PCB)-based scheme using state-of-the-art electronics for costeffectiveness and fully digital control. Testing results show that the unipolar pulse can reach over 165 Vpp with a 6-dB bandwidth of 70 MHz, and the bipolar pulse and arbitrary pulses can reach 150 and 60 Vpp with central frequencies of 60 and 120 MHz, respectively.
高频（>20MHz）超声（HFUS）成像系统使得对具有精细空间分辨率的小结构进行成像成为可能。它们在皮肤科、眼科、血管内成像和小动物成像中找到了各种生物医学应用。HFUS 的一个关键技术挑战是生成高压、高频脉冲信号，以有效地激励换能器，实现高信噪比。本文介绍了一种用于 HFUS 成像的多功能、可重构脉冲发生器的开发。该脉冲发生器可以产生高压单极脉冲、双极脉冲或用于 B 模式成像、多普勒测量和调制激励成像的任意脉冲。通过高速现场可编程门阵列（FPGA）可以对脉冲的特性（如定时、波形和频率）进行可重构。定制软件通过 USB 连接器与 FPGA 接口，用于脉冲选择和轻松、灵活、实时的脉冲管理。该硬件采用基于印刷电路板（PCB）的紧凑设计，使用最先进的电子技术实现了成本效益和全数字控制。测试结果表明，单极脉冲的峰峰值可达 165Vpp，带宽为 70MHz，6dB；双极脉冲和任意脉冲的峰峰值分别可达 150Vpp 和 60Vpp，中心频率分别为 60MHz 和 120MHz。
