Preliminary study of Automatic Control Gain loop subjected to pulse-modulated radiofrequency interference

The paper presents a detailed study of the dynamic response of an Automatic Gain Control loop (AGC loop) exposed to pulsed radiofrequency interference. It is shown that the most significant effect is an increase of the RF output level of the AGC that is strongly dependent on the pulse repetition frequency, the effect being less pronounced as the repetition frequency increases. It is demonstrated that this is related to the transient response of the logarithmic amplifier, which can be controlled by decoupling capacitors.