The effects of ADC nonlinearities on digital beamformers

The output beam pattern of a digital beamformer (DBF) using the full dynamic range of a high-speed (HS) analog-to-digital converter (ADC) was investigated. A simple model for the full-range HS ADC nonlinearity was developed. It is shown that the nonlinearities in an HS ADC can cause substantial degradation in a digital beamforming array when interference is present. This degradation is caused by the appearance of 'phantom' interferers created by the nonlinearity of the ADCs. These phantom interferers are harmonics of the original interferer and signal.<
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