Frequency Domain Adaptive Decoupling in Multiple Output Array Processors.
PENNSYLVANIA STATE UNIV UNIVERSITY PARK APPLIED RESEARCH LAB
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This research is concerned with reducing the deleterious effects of undesired signals which are received through the side-lobes of an array in a multiple output array processor. Two forms of beam decoupling systems are suggested. The first is a non-iterative form which, in general, requires a matrix inversion of a power spectral density matrix and the second more useful form is an adaptive algorithm that avoids the direct matrix and the attendant computational requirements of this inversion. This iterative algorithm operates in the frequency domain and in real time to reduce the mean square coupling between fixed adjacent preformed beams. A discrete frequency domain approach is used to avoid time-delay networks which would be needed in a time domain decoupling system. In addition, a frequency domain system offers frequency selectivity in that, at each discrete frequency, beam decoupling can be effected. The beamformer relationship for a multiple output linear beamformer is developed in both the frequency domain and the time domain. These relationships are derived in matrix form. Several relationships for decoupled array processors are also derived in matrix form. These relationships result in diagonal forms of output or input-output power spectral density matrices for decoupled systems. The theoretical development of non-iterative decoupling processors is given.