A folding adaptive equalizer is provided. The equalizer comprises an equalizer core and an automatic gain control loop. The equalizing transfer function of the equalizer core is modulated by one or more gain control signals generated by the automatic gain control loop and by a folding signal generated by the automatic gain control loop. When the folding signal is inactive, an increase in the gain control signals produces an increase in the high-frequency, high-bandwidth gain of the transfer function of the equalizer core. When the folding signal is active, further gain can be applied by decreasing the gain control signals, which produces a frequency-shift in the transfer function of the equalizer core toward lower bandwidth and an increase in the high-frequency, low-bandwidth gain of the transfer function of the equalizer core.