F-t rada receiver with level discrimination

Claim 1

A receiver for a RADA system including frequency slot means for selecting from incoming radio frequency signal pulses the ones of said pulses having a frequency corresponding to any of the frequency slots assigned to said receiver, said ones of said pulses being frequency selected pulses, time slot means for selecting from said frequency selected pulses each group of said frequency selected pulses which correspond in frequency and time relationship to the frequency/time slot address of said receiver, said last mentioned selected group of pulses being time slot selected pulses, and automatic gain control amplification means for controlling, in response to a gain control signal, the levels of said frequency selected pulses, wherein the improvement comprises limiter means connected to receive said frequency selected pulses and responsive to a limiter control signal for selectively limiting the levels of said frequency selected pulses to a first predetermined high level and to a second predetermined medium level when said limiter control signal has a first and a second value, respectively, analog to digital converting means, connected to receive said frequency selected pulses from said limiter means, for converting each said frequency selected pulse into a quantized signal with respect to a modulus representative of said first predetermined high level, comparator means connected to receive said quantized signals for comparing said quantized signals with one another to produce a comparator output quantized signal representative of a level which is at most equal to the minimum of the quantized signals compared, first level selector means connected to said comparator and responsive to said comparator output quantized signals for producing a series of first level selector output pulses when the levels of said comparator output quantized signals are equal to or higher than a third predetermined level which is lower than said second predetermined level, second level selector means connected to said comparator and responsive to said comparator output quantized signals for producing said gain control signal for reducing the gain of said automatic gain control amplification means when said comparator quantization signal levels are at least equal to said second predetermined medium level, and limiter control signal producing means responsive to the outputs of said first and second level selector means for producing said limiter control signal of said first and said second values when the comparator output quantization signals fall within a range between said third and said second predetermined levels and outside thereof, respectively, said second predetermined level comprising the highest quantization level with respect to said modulus.