Abstract: The invention relates to apparatus for reducing the masking effect in the doppler frequency domain of wind sheared clutter upon the radar returns of moving targets. The invention consists in forming two beams from the elements of a radar antenna array by means of adjustable complex weights which are then summed. One of the two beams is then delayed by a predetermined amount and added algebraically to the other beam to form a composite beam containing a narrow trough-like depression in beam angle/doppler frequency space. Means are then provided for adjusting the weights to bring coincidence between the depression and the clutter to cause attenuation of the clutter with a minimum reduction in the usable doppler frequency domain.

Abstract: 1. In an undesired signal canceller, a main signal transmission channel having an output terminal, a plurality of auxiliary signal transmission channels having output terminals, means for cross coupling each of said auxiliary channels separately to said main signal transmission channel, means for generating error signals representing the relative amplitude and phase of each undesired signal in the auxiliary channels cross-coupled with undesired signals in the main channel, compensating cross feed networks capable of adjustment for minimizing cross coupling at said main channel output terminal, and means responsive to said error signals for adjusting said cross feed networks in order to minimize cross coupling.