Radar System Engineering

554 THE RECEIVING SYSTEM-INDICATORS [SEC. 13.21
Asthesignal level increases, thelast stage saturate sandcancontribute
no more. By this time, however, the contribution from the preceaing
stage has become appreciable and the output continues to increase,
but at a lower rate than that occurring when the gain of the last stage
was included. Eventually the second stage saturates, and the gain
drops to that from the next preceding stage, and so on. Thus the total
signal range is compressed, but there is no complete saturation even on
very strong signals. Such receivers have not had very extensive tests
with conventional airborne radar, but the rather meager results have
shown promise. One variant that has not been tried, to the author’s
knowledge, is to use different saturation (or limit) levels in the various
channels, as in the three-tone method, making this a “multi-tone”
device.