Channel assignments for improved gain in baseband array feed compensation systems

The performance of a real-time digital combining system for use with array feeds has been considered in previous articles. The purpose of the combining operation is to recover signal-to-noise ratio (SNR) losses due to antenna deformations and atmospheric effects. Previously, arbitrary signal powers and noise variances were assumed, but no attempt was made to match the receiver channels to the available signal powers. Here it is shown that for any signal power and noise variance distribution, a “best” channel assignment exists that maximizes the combined SNR in the limit of vanishingly small combining losses. This limit can be approached in practice by observing sufficiently many samples. Specific signal power and noise variance distributions are considered, and it is shown that even relatively “noisy” channels can be used effectively to recover SNR losses resulting from signals diverted out of a “high-quality” channel by antenna deformations