Design and implementation of a digital phase shift beamformer

This paper describes the design, implementation, and performance of a digital beamformer conceived in the late 1960’s to replace the mechanical video scanning switch found in many sonar systems of that time. The design goals included preserving the wide dynamic range typical of high powered sonars, increasing the scanning rate to be commensurate with system bandwidth, and providing sonar data in digital form for studies of post‐beamforming processing. In Sec. I, a digital beamformer which uses geometric quantization of quadrature sampled stave data is described, and its properties are obtained via computer simulation for a circular array geometry. The combination of digital phase shift beamforming with circular array geometry leads naturally to a serial implementation, which amounts to a ’’finite impulse response (FIR)’’ filter, to obtain a scanned beam output. One version of this implementation was built and tested. Brief descriptions of the hardware and its measured properties are given in Sec. II.