Translations:Prediction-error filters/23/en

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Figure 6a (left) show a mixed-delay wavelet with the same autocorrelation as that of the minimum-delay wavelet in Figure 5a (left). This mixed-delay wavelet is obtained from the minimum-delay wavelet by passing the minimum-delay wavelet through an all-pass filter. We proceed as before. Figure 6a (right) shows the desired output for a prediction distance of two. This desired output is the wavelet advanced by two time units to the left — that is, the first nonzero coefficient of the desired output occurs at negative time . Figure 6b (left) shows the unit-distance prediction filter, which is the same as that in Figure 5b (left). Figure 6b (right) shows the prediction. Now, however, we note that the values for nonnegative times no longer agree with the desired output, as was the case for the minimum-delay input. On the other hand, the filter cannot reach the values of the desired output for negative times. These values give the so-called unreachable prediction error, which for the case of prediction distance two is simply two spikes. Figure 6c (left) shows the prediction-error filter, which is the same as that in Figure 5c (left). Figure 6c (right) shows the difference between the desired output and the prediction. The output of the prediction-error filter is this difference delayed by two time units (i.e., by the prediction distance).