The effects of cross-correlated noise and multi-channel signal on ORing loss

To reduce the amount of information presented to a human observer, ORing has been used to combine frequency-time plots from several acoustic channels. ORing introduces a loss which is measured as a rise in the minimum detectable signal-to-noise ratio. Equations for ORing loss are derived for a general signal processing system with arbitrary signal and noise distributions. Results are provided for the case of Gaussian noise and Gaussian signal. Simulation is used to verify the analytical results, and to provide insight into how cross-correlated noise and signal present on multiple channels reduce ORing loss. Results suggest: 1) if signal is present on only one channel, noise correlation reduces ORing loss, but not as much as currently estimated, and 2) if noise is independent from channel to channel, signal on more than one channel also reduces ORing loss. However, the two effects are not independent. Consequently, they must be considered together when estimating ORing loss.