457374.fig.0013a
(a)
457374.fig.0013b
(b)
457374.fig.0013c
(c)
457374.fig.0013d
(d)
Figure 13: Group delays of the digital filters in the ARA equalizer: (a) the first-order Butterworth highpass filter, (b) the biquad peak filter, (c) the biquad notch filter, and (d) the combined delay of the three filters.