Polarity Coincidence Arrays
Clarence S. Clay · The Journal of the Acoustical Society of America · 1970
The purpose is to examine the performance of a multiple polarity signal-processing system for an array having a small number of channels. The system has a narrow directional response and small side lobes for CW signals. In the m-channel system, the instantaneous signals are sampled to determine the sign of the signals. If all m channels have the same sign, the output is 1 and otherwise the output is 0. The system performance is measured by the ratio of the mean output of system sN to the standard deviation of the output σN. Gaussian noise is assumed to be in each channel and is uncorrelated between channels. At small input-signal to noise-power ratios, sN/σN was proportional to the input-signal to noise-power ratio, N12 and f(m), where N is the number of independent observations and f(m) is a system function. f(m) has a maximum value at m = 6. The response of a six-receiver array was simulated on a delay line. The signals were delayed the times 0, T, 2T, 4T, 7T, and 13T. For a CW signal, the output was 1 at the frequency T−1, and the null-to-null width of the main lobe was (15T)−1. The side lobes were less than 0.1.