Figure 2From: Comparison of spectral estimators for characterizing fractionated atrial electrogramsMechanism by which the average autocorrelation spectrum sharpens as n lags are added to form the average. A. The autocorrelation function. B. Lag vectors. The frequency range shown in panels C and D, 2-20 Hz, corresponds to w = 500–50 sample points for the signal digitized at 977 Hz.Back to article page