The Video Limiter Circuit
The better way to limit the signal is while preserving all information contained in the signal is by soft limiting the signal, where the signal will be compressed at the above threshold region. The LT1228 is used here in a slightly unusual, closed-loop configuration. The gain of the closed-loop is set by the feedback and gain resistors (RF and RG) and the open-loop gain by the trans-conductance of the first stage times the gain of the CFA. The level at which the limiting action begins is adjusted by varying the set -current into pin 5 of the trans-conductance amplifier.
[Schematic diagram source: Linear Technology Application Notes]