Cascade preprocessors for adaptive antennas

Adaptive preprocessors placed in cascade ahead of the main adaptive processor circuits of an adaptive array can improve settling rate appreciably and help offset the slow convergence of gradient type algorithms (Widrow, Applebaum, or Griffiths algorithms). The piecemeal approximation is adequate in practice and does not require recursive procedures. The adaptive preprocessing networks are arranged to resolve input signals into eigenvector components, even when the solution for the eigenvector components is approximate. The signal/interference ratio can be improved even without identification of the desired signal, a definite advantage in signal acquisition with spread spectrum techniques in antijam communications systems. Accelerated convergence techniques are indicated.