Abstract: An adaptive RADAR environmental signal filter (1) is described which selectively preprocesses RF RADAR input data prior to the data's utilization by a processor (8). The filter (1) consists of an array of parallel discriminator cells (165) which compare incoming RF RADAR data to a window parameterized by predetermined threshold values. The array of discriminator outputs are networked through combinational logic (59) in order to provide an output correlation signal (63) to an external processor (8). A discriminator enable latch (55) synchronizes the discriminator outputs as the outputs pass through the combinational logic (59).