J. O. Coleman

TITLE:

Front-End IMD in Receive Arrays: How Beamforming Sums Combine ADC Spurs

AUTHORS:

J. O. Coleman

ABSTRACT:

Here the effects of placing an identical memoryless nonlinearity behind every element of an active receive array are first reviewed, following which several recently proposed ideas for mitigating nonlinear distortion in all-digital arrays are briefly examined. Examples assume an RF-sampled S-band radar receiver, even though the concepts apply to IF-sampled systems as well. A chirp waveform with a substantial time-bandwidth product is assumed in places as well. A nonlinearity prior to the RF filter, presumably in a low-noise preamp, is considered briefly, but the focus is on distortion introduced by the ADC that presumably follows the RF filter.

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STATUS:

Published March 7, 2024 as NRL Memorandum Report NRL/5320/MR--2024/2. Approved for public release; distribution is unlimited.

DATE OF ENTRY:

September 2024.