A Low-Power Wide-Dynamic-Range Analog VLSI Cochlea

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. In this paper, we describe an analog electronic cochlea that processes sounds over 6 orders of magnitude in intensity, and that dissipates 0.5 mW. This 117-stage, 100 Hz to 10 KHz cochlea has the widest dynamic range of any artificial cochlea built to date. The wide dynamic range is attained through the use of a wide-linear-range transconductance amplifier, of a low-noise filter topology, of dynamic gain control (AGC) at each cochlear stage, and of an architecture that we refer to as overlapping cochlear cascades. The operation of the cochlea is made robust through the use of automatic offset-compensation circuitry. A BiCMOS circuit approach helps us to attain nearly scale-invariant behavior and good matching at all frequencies. The synthesis and analysis of our artificial cochlea yields insight into why the human cochlea uses an active traveling-wave mechanism to sense sounds, instead of using bandpass filters. The low power, wide dynamic range, and biological realism make our cochlea well suited as a front end for cochlear implants.     

一种高速、宽动态范围检波器的研制

微波检波器具有结构简单、使用方便的特点,是射频微波领域的一种常用器件。基于微带混合电路技术,研制了一种高速、宽灵敏度动态范围的脉冲检波器。仿真设计了带宽为5.6~13.8 GHz的宽带带通滤波器和3 GHz的宽阻带低通滤波器作为检波器的输入输出电路。该检波器可以对6~12 GHz频段内、功率为-8~16 dBm的脉冲调制信号进行检波,灵敏度动态范围约25 dB,响应时间小于3~4 ns。