Designing filters for interpolation beamforming

The concept of Interpolation Beamforming was devised by Pridham and Mucci [1, 2] to allow the outputs of the sensors in an array to be sampled at a lower rate than usually required for beam-forming. In this paper we consider the design of the required Interpolation Filter. By introducing an equivalent processing structure, we are able to derive a design procedure that accommodates the requirements of the beamforming operation for the smallest errors at the highest frequencies. An example of the use of the method is presented. We also introduce a variation of the method that permits the minimization of the interpolation error at a specific frequency.