Comparison of three correlation coefficient estimators for gaussian stationary processes

Using independent samples from two stationary Gaussian processes, second-order statistics are examined for the following three correlation estimators: 1) the direct estimator, 2) a "hybrid-sign" estimator, and 3) the polarity coincidence estimator. In most cases, increasing the number of samples by a factor of two or three allows one to use the simple polarity coincidence estimator with the same accuracy as the other two estimators.