On the design of the target-signal filter in adaptive beamforming

This paper deals with the improvement of jammer suppression for adaptive broadband beamforming. The analysis is carried out with a two-microphone Griffiths-Jim beamformer and one jammer signal. By examination of the derived optimal filter, a design strategy for the constant target signal filter in the main channel of the beamformer is given. This leads to a substantial reduction in the required filter length of the adaptive filter while maintaining the same jammer suppression. Furthermore, a faster rate of convergence can be achieved, as there are less filter coefficients that have to be adapted. Finally, it is shown that the design strategy also applies if more than two microphones are used