Why do we need AGC？

AGC is short for Automatic Gain Control,  which is used to amplify signals of different strengths with different gains so that the final output amplitude of the signal is maintained at the same standard. We know that in addition to AGC, we also have automatic level control (ALC), so why do we still need automatic gain control?

From the perspective of Automatic Level Control, if there is only automatic level control, then the voltage control is a ruler with a range, and the accuracy is limited. Therefore, when the signal or voltage level is too low or too high, the accuracy of the automatic level control will be non-reference. The best way is to amplify the measured value to automatically control its own gain so that the output signal can always be kept at the same level, regardless of the strength of the input signal, this is also Automatic Gain Control(AGC).
Common receivers almost always have AGC setting items to further ensure the rationality of IFG and RFG, so when setting IFG, RFG and AGC, you need to consider overall and adjust in time.