Figure 4

AGC thresholds: IF stage. The second AGC loop entails respectively an upper and lower threshold. The upper-threshold can be set to the highest detected signal within a specific frequency range (typically tens of MHz) which depends on the AGC settling time. The lower threshold may be defined on a fixed distance from the upper-threshold, i.e., in this case 40 dB. As a result the signals are pulled up by the IF-gain.