程控增益放大器及其与微机的接口技术

A Programmable Gain Amplifier and Its Interface with Microcomputer

分析一种由单片数模转换器构成的数字程控放大器的原理 ,给出该程控增益放大器的两种结构 ,并对其中一种给出设计示例及测试结果 .测验表明这种程控增益放大器的增益控制精度高 ;该放大器易于微机接口 ,文中给出一种接口电路实例 .本文讨论的程控增益放大器性价比高、电路结构简单、可靠性好、通用性强 。

This paper analyses the theory of one type of program controlled gain amplifier (PGA) made of D/A converter (DAC). Tow types of PGA are presented. A circuit of one type is built. Measurement to the characteristics of the amplifier is taken. Experimental result shows this type of PGA has high precision of gain control. The PGA can interface with microcomputer easily. One type of the interface circuit is given. This type of PGA is of low cost, simple circuit and universal. It can be applied in low frequency intelligent instruments and industry control systems.