RF CHANNEL AMPLIFICATION MODULE WITH INSTANTANEOUS POWER LIMITING FUNCTION The present invention relates to a radio frequency channel amplification module with instantaneous power limiting function. It applies particularly to the field of communication satellites, and more specifically to 10 the pre-amplification of the input signals of the radio frequency power amplifiers of travelling wave tube type equipped or not with linearization means by predistortion. In telecommunication satellites, it is necessary to amplify radio 15 frequency signals received in order to retransmit them, via transmit antennas, to subscribers, that is to say receiving stations, for example situated on the ground or in airborne carriers. The devices embedded in the satellites making it possible to retransmit the radio frequency signals are commonly called "repeaters". A repeater comprises communication subsystems or channels 20 and each communication subsystem can typically comprise, in its output section or "downlink channel", one or more travelling wave tube amplifiers, linearized or not, commonly designated (L)TWTA, which stands for "(linearized) travelling wave tube amplifier", the travelling wave tubes commonly being referred to by their acronym TWT. For optimum 25 performance, a TWT is usually used close to its saturation region, and constitutes an equipment item that is particularly sensitive to input levels above its saturation power. Excessively high input levels can in fact result in deterioration, even destruction, of the TWT. An application of input levels above an acceptable threshold is commonly referred to by the term 30 "overdrive". According to known techniques, an amplification module of channel amplifier type can be arranged upstream of the LTWTA, making it possible to condition the radio frequency signal applied as input to the TWT, notably via a pre-amplification. Known channel amplifiers are,"for example, called CAMP, 35 which stands for "Channel AMPIifier", or even "DLA", which stands for "Driver Limiter Amplifier". Typically, a linearized travelling wave tube amplifier 4 LTWTA benefits from an output power limiting function that mal