大动态高速响应数字AGC功能电路的实现

Realization of Large Dynamic High-speed Response Digital AGC Function Circuit

为了提高接收机系统的动态范围和抗干扰能力,改善ADC电路的工作性能,设计了一款多功能、高性能、反馈式数字AGC电路。以大动态高线性对数检波器和高精度数控衰减器为核心射频电路,以MCU、ADC、ASIC为核心控制电路,由RS485接口电路实现AGC电路与上位机的通信功能,并通过仿真优化了数字AGC软件算法。测试结果表明,该数字AGC电路具有初始态满衰减保护功能、两种工作状态的控制功能、与上位机的双向通信功能,并且工作参数可以灵活设置。在-55~+85℃温度范围,100 MHz~1 GHz的工作频率下,该数字AGC电路对单音信号的动态响应范围为62 dB,输出功率稳定度为±1.5 dB@-38.5 dBm,最快响应时间为22.6μs。

In order to improve the dynamic range and anti-interference ability of receiver system and the performance of ADC circuit,a multi-function,high performance and feedback digital AGC circuit was designed.In this paper,a large dynamic high linear logarithmic detector and a high precision numerical control attenuator were used as the core RF circuits,MCU,ADC,ASIC were used as the core control circuits,and RS485 interface circuit was used to achieve the AGC circuit and the host computer communication function.The digital AGC software algorithm was optimized by simulation.The test results show that the digital AGC circuit has the function of full attenuation protection in the initial state,the control function of two working states,the bidirectional communication function with the host computer,and the working parameters can be set flexibly.Under the temperature range of-55-+85℃,the operating frequency of 100 MHz-1 GHz,the dynamic response range of the digital AGC circuit to single tone signal is 62 dB,the output power stability is±1.5 dB@-38.5dBm,and the fastest response time is 22.6μs.