Patent US 4,044,352

This invention relates to an improved signal processor that is insensitive to the type of clutter that is encountered by utilizing multiple parallel range sample intervals which vary in length from minimum to maximum so that the optimum sample size is provided for clutter or different range extents. By utilizing the correct range sample interval for the clutter, the detection threshold is accurately set as a result of an improved sample mean. The detection system includes a plurality of mean level processors operating in parallel in response to signal samples varying from minimum to maximum length in range and a selection circuit that selects the largest amplitude value of the clutter signal for use as the mean value in a signal comparator. When the mean value is the same for two or more sample sizes, one arrangement in accordance with the invention utilizes the larger sample size as the mean value.