Perturbation adaptive array processor for airborne application

The adaptive processor here described uses a perturbation algorithm embodied in a microprocessor, and has been used with a four-element array. The resulting system is of low cost and great flexibility, with particular advantages for installation in aircraft. The transient response is shown to be of the same form as that of an LMS algorithm for small perturbations, and a simulation shows the deviations from this form for larger perturbations. The simulation also provided some interesting examples of processor behaviour, as well as being used to determine several design parameters. The use of a microprocessor allows more complicated features to be used than is possible with dedicated hardware. An example is the weight rescaling process which takes the place of the clamped weight or reference signal. The hardware description includes the highly successful weight linearisation technique used. Good linearity keeps to a minimum the word length used for weight control, and is essential to the weight rescaling process.