Abstract: An adaptive antenna array system steers a plurality of antennas to direct e null toward an undesired source of interference to reduce noise and enhance detection of desired signals. A null indication processing system adjusts the phase and amplitude of the antenna branches to steer the null and provide a null angle indication and display. Digital controller and memory circuits provide automatic operation.

Abstract: The delay line has a number of sections in tandem. Each section comprises o line segments in parallel, one of which is relatively short and the other of a length to provide a given differential delay for the section. Each segment has a PIN diode at each end, poled in one direction for the short segment and in the other direction for the other. The bias arrangement for the PIN diodes includes four transistor switches in a bridge, with a selected pair in opposite legs turned on to cause a polarity which permits it to flow through only that segment in which the PIN diodes are forward biased. The given differential delay for the several sections has a binary relation.

Abstract: According to the invention, a receive-transmit steerable null antenna prosor includes incrementally adjustable delay lines and a variable ratio power network (amplitude balance control) for adjusting the relative phase and amplitude in two or more antenna branches to steer a null on an interference source. A digital controller compares a signal which includes a representation of the interference level to a previously sampled value to note improvement or not and adjusts the delay lines and amplitude balance accordingly.

Abstract: A system employing broadband radio frequency vector multipliers in a balang process for nulling out unwanted radio frequency signals. The nulling is achieved by adjustment of both the desired and interference signals as they pass through the system. The adjustment is accomplished by using vector multipliers which shift the phase by equal amounts and vary the amplitude by proportionate amounts of one or more radio frequency signals in response to separate phase shift and amplitude control forces. To obtain a desired phase shift, an incoming radio frequency signal is split into 0.degree. and 90.degree. components. By multiplying the 0.degree. component by the cosine of the desired phase shift angle, multiplying the 90.degree. component by the sine of the desired phase shift angle, and then summing the results, the signal can be phase shifted by any amounts through all four quadrants.