Externally Linear Low-Power Analog Signal Processing Circuits

[02091099]本研究探讨了利用内部非线性系统进行线性模拟信号处理的可能性。上下文是完全集成的系统，在单个硅芯片上制造，包含数字信号处理器或计算机加模拟信号处理器；后者通常是物理世界接口的必要组成部分。实现模拟处理器的传统线性技术通常会导致非常大的能量消耗，这使得它们在许多实际情况下被排除在外。我们正在研究使用内部非线性处理器来绕过这些限制。这项工作的应用范围从无线通信和计算机硬件延伸到消费产品和生物医学仪器。允许内部非线性的输入-输出线性信号处理器的使用允许内部信号在较大的输入信号范围内具有远高于噪声和干扰的幅度，同时保持安全低于过载水平。结果是在整个输入范围内具有足够的信噪比，而不需要大的功耗和芯片面积。其他一些相关的想法也正在研究中。一种是使用动态偏置，其中动态模拟电路（如滤波器）的偏置电平根据信号电平动态变化；另一种是使用多个信号处理器，每个处理器根据需要动态地放置在信号的路径上。由于当动力系统内部参数发生变化时，通常会产生输出扰动，因此如何消除或防止这种扰动的发生是本研究的一个关键考虑因素。

ABSTRACT0209109Columbia UYannis TsividisThis research explores the possibilities of performing linear analog signal processing using systems which are internally nonlinear. The context is fully integrated systems, fabricated on a single silicon chip, containing a digital signal processor or a computer plus an analog signal processor; the latter is often a necessary part of the interface to the physical world. Conventional linear techniques for implementing analog processors often result in very large energy consumption, which rules them out in many practical cases. We are investigating the use of internally nonlinear processors to bypass those limitations. The applications of this work extend from wireless communications and computer hardware to consumer products to biomedical intrumentation.The use of input-output linear signal processors which are permitted to be internally nonlinear allows the internal signals to have, for a large input signal range, a magnitude well above that of noise and interference, while at the same time remaining safely below overload levels. The result is an adequate signal-to-noise ratio over the entire input range, without requiring large power dissipation and chip area. A number of other related ideas are being investigated as well. One is the use of dynamic biasing, in which the bias levels of dynamical analog circuits, such as filters, are dynamically varied depending on the signal level; the other is the use of multiple signal processors, each being placed dynamically in the path of the signal as required. Since output disturbances would normally occur when the internal parameters of a dynamical system are varied, a key consideration in this research is how to eliminate such disturbances or prevent them from occurring.