关键词: 动态范围, AGC, AD8367

Abstract: The VGA device AD8367 of Analog Device is introduced in this paper, including its main performance and device features .On this basis, with its built-in detector to constitute gain negative feedback loop, the IF AGC circuit with more than 75 dB dynamic range is designed and presented.This circuitconsists of two-stage AD8367, middle IF amplifier and four L-shaped broadband resistance matching network, which is capable of automatically adjust overall gain to analyse magnitude diversed signals. During the debugging process, signal level and I/O matching network are chosen carefully to maximize AGC dynamic range. Finally, test results show that this design satisfies receiver requirements, in spite of a little bit distortion.

Key words: dynamic range, AGC, AD8367