Energy-efficient adaptive signal decomposition: the silicon and biological cochlea

We describe an analog electronic cochlea that decomposes sounds over 6 orders of magnitude in intensity into 117 channels over a frequency range of 100 Hz-10 khz while dissipating less than 0.5 mW. This cochlea has the widest dynamic range of any artificial cochlea built to date. The design, using frequency-selective automatic gain control in a low-noise traveling-wave amplifier architecture, yields insight into why the biological cochlea uses a traveling-wave mechanism to decompose sounds, instead of using bandpass filters