Accumulator radar echo detector

Claim 1

An accumulator radar echo detector for generating continuous target indication signals at associated range rings of a PPIradar screen comprising a quantizing echo signal converter for transforming each input pulse which exceeds a reference peak into impact signals prolonged for a predetermined duration, a timing signal generator having an output, register means coupled to said timing signal generator, responsive to timing signals from its output, and having an input stage and an output stage, and means which in dependency upon whether a stored summation value supplied to inputs thereof from said output stage is or is not supplemented by an impact signal supplied to another of its inputs from said quantizing echo converter increases by a number of units the stored summation value or reduces such by a unit and which upon exceeding a predetermined minimum summation value produces a target presence signal on at least one of its outputs and upon subsequent dropping below such minimum summation value resets the stored summation value to the starting value null, said means being a fixed programmed read only memory which in accordance with a predetermined assignment table for each possible total condition combinations at its said inputs generates a respective predetermined total condition combination at its output, a partial combination at this output being coupled to said input stage of said register means as sole input to said register means other than that from said timing signal generator.