J. O. Coleman

Spatio-Temporal Delta-Sigma Modulation for Shared Wideband Transmit Arrays
Dan P. Scholnik and Jeffrey O. Coleman, Donald Bowling, and Michael Neel
Future array-based RF systems will require linear amplification to preserve the spectral integrity of simultaneously transmitted signals. Classical delta-sigma modulation, paired with an emerging class of high-power switches, can provide this linearity by using a high-speed, low-resolution quantizer and shaping the resulting quantization errors out of the signal band. The drawback is that high clock rates are required to achieve high SNR. Recently we have proposed jointly shaping quantization errors in temporal and spatial frequency, pushing quantization errors both out of band and to non-propagating spatial frequencies. This provides greater SNR for a given clock rate or the same SNR at a reduced clock rate relative to conventional delta-sigma modulation, while retaining its characteristic high linearity. In this paper we present an overview of the spatiotemporal delta-sigma array architecture and present the results of some preliminary hardware experiments with a small linear array.
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Presented to the 2004 IEEE Radar Conference (RADAR 2004), Philadelphia PA, USA, April 26-29, 2004,
June 2004.