高频程控增益前置放大器的设计及其在医学仪器中的应用

目的：设计一种高频程控增益前置放大器，以满足“便携式数字型医用超声声功率计”研究的需要。方法：根据医用超声源频率范围宽、输出功率相差悬殊的特点，权衡便携、低功耗与低失真度、价格等因素，针对不同应用条件，制作出分别由集成电路和分立元件构成的两种结构不同的高频程控增益前置放大器，经调试、优化后，应用到医用超声声功率计中。结果：两种电路分别应用于“便携式数字型医用超声声功率计”，经试用，效果良好。结论：实践证明，由集成电路组成的放大器具有体积小、功耗低、电路结构简单、易与微处理器接口等优点，但它对器件依赖性强，信号保真度差，价格昂贵；而分立元件组成的放大器虽然体积、功耗、与微处理器接口等方面逊于前者，但它元器件易得，信号保真度好，价格低廉。在体积、功耗等条件许可的情况下，该放大器不失为上乘选择。

The design of the program-controlled high frequency gain preamplifier and its application in medical instruments

This article introduces the design of two types of the program-controlled high frequency gain preamplifier for the project of medical ultrasonic dynamometer,by using the ultrasonic signal's characters of high frequency and wide range ultrasonic power.Its application in clinic proves that the amplifier consist of discrete units and the amplifier consists of ICs are almost the same for having small volume,low dissipation,simple structure and so on,but the former is batter than the latter for having low signal distortion,thus the former is recommended.