摘要
对数放大器实实质上就是一种对数变换器,是指输出信号幅值与输入信号幅值呈对数函数关系的基本放大电路。在电子测量技术领域之中,某些信号的电压具有比较宽的动态范围,例如在雷达、声纳等无线电接受系统中,接收机前端信号动态范围可以达到120d B甚至更高。一般的线性放大器不能处理这样宽的动态范围,为了更加方便的测试和分析这些信号,在线代测量接收机的设计中,采用大动态范围对数放大器设计技术。本文介绍了一种核心器件为AD8306的大动态范围对数放大器的设计,实现了90d B的动态范围,宽带频率,灵敏度高。采用该方法实现的对数放大器动态范围大,电路简单易于实现,如果采用多片芯片级联还可以实现更大动态范围的对数放大器。实际应用表明,本文给出的设计方法合理有效,具有很高的使用价值。
Log amplifier is actually a log converter, it is a amplifying circuit that the relationship between the output signal amplitude and the input signal amplitude is a log function. In the field of electronic measurement, some signals have very high dynamic range, such as in the radar system, sonar system and so on, the signal dynamic range in the front of the receiver can be more than 120 d B. Linear amplifier cannot handle such a wide dynamic range. In order to measure and analyze these signals expediently, modern measurement receiver used to adopt a design of large dynamic range log amplifier. This paper introduced a design of large dynamic range log amplifier based on AD8306, with 90 d B of dynamic range. Making use of this method, the log amplifier dynamic range is very large, and besides, this circuit is very simple and effective. If we use more than one chips,we can achieve larger dynamic range. This practical applications show that the design method is valid and practical.
出处
《电子设计工程》
2016年第6期61-63,共3页
Electronic Design Engineering
关键词
测量
对数放大器
宽带
大动态范围
measurement
log amplifier
broad band
large dynamic range
