System for providing a summarized information on the line spectrum from a Doppler radar spectrum analyzer

Claim 1

A Doppler radar plot summarizer for moving targets supplying a digital signal for one or more targets, said signal for each target range called an elementary summary plot, PRE, corresponding to a given delay of the received signal, said digital signal consisting of one target detection bit D, one bit V indicating whether the target is a single-speed target and one word of m+1 bits containing information on the speed of that target, if the target is of a single speed, wherein said plot summarizer receives a digital signal called an elementary raw plot, PBE, from a circuit comprising in series a 2 m point spectrum analyser, made up of a weighting circuit, a 2 m Fourier transform calculator and a modulus extractor, and a contrast detector furnishing, for each of these target ranges, said elementary raw plot consisting of one word of 2 m bits, the weighting performed by said weighting circuit being such that it limits the maximum number of cyclically contiguous lines for which a single-speed target is detected to 2 m /4+1, said plot summarizer comprising: four read-only memories respectively addressed by a first, a second, a third and a fourth group of bits of said elementary raw plot and providing at their outputs corresponding digital signals of m+3 bits called pseudosummaries, said first group consisting of bits 0 to 2 m-1 -1 of the elementary raw plot, said second group consisting of bits 2 m-2 to 2 m-1 + 2 m-2 -1 of the elementary raw plot, said third group, complementary to said first group, consisting of bits 2 m-1 to 2 m -1 of the elementary raw plot and said fourth group, complementary to said second group, consisting of bits 2 m-1 +2 m-2 to 2 m -1 and 0 to 2 m-2 -1 of the elementary raw plot; and a logic circuit for reconstituting said elementary summary plot from said pseudosummaries provided by said four read-only memories.