Abstract:

Low-power wide-dynamic-range systems are extremely hard to build. The biological cochlea is one of the most awesome examples of such a system: It can sense sounds over 12 orders of magnitude in intensity, with an estimated power dissipation of only a few tens of microwatts. An analog electronic cochlea that processes sounds over six orders of magnitude in intensity, while dissipating less than 0.5 mW, is described. This 117-stage, 100-Hz to 10-KHz cochlea has the widest dynamic range of any artificial cochlea built to date. This design, using frequency-selective gain adaptation in a low-noise, traveling-wave amplifier architecture, yields insight into why the human cochlea uses a traveling-wave mechanism to sense sounds, instead of using bandpass filters.