Impact of beam steering errors on shifted sideband and phase shift beamforming techniques

The Shifted Sideband Beamformer (SSB) is a digital, time‐domain beamformer intended for bandpass applications. Computational efficiency results from the digital processing of the complex envelope of the sensor data at a rate proportional to the bandwidth of the data. In a previous paper, the spatial response of the SSB was examined and compared to that of a conventional bandpass digital beamformer by modeling the beam steering quantization error as a uniformly distributed random variable. This paper examines, in detail, the specific case of a line array of uniformly spaced sensors where beam steering quantization is shown to produce systematic time‐delay errors for both the conventional beamformer and SSB implementations. Expressions are presented for predicting the directions of grating side lobes in the spatial response pattern as a result of these errors. Also, the spatial response of the Phase Shift Beamformer (PSB), which is a limiting case of the SSB and intended for narrow‐band applications, is exa...