Analog Hardware Implementation of AdaptiveFilter

We have implemented a four-tap adaptive lter in a continuous-time analog VLSI circuit. Since an ideal delay is impossible to implement in continuous-time hardware, we implemented the delay line as a cascade of low-pass lters (called the Gamma lter). Since many years of research in our lab has shown that the Gamma lter outperforms the delay line for a wide range of applications, the Gamma lter should not be considered merely a crude approximation of the ideal delay line. For the rst time, we show measured results from an analog chip for the problem of system identiication{identifying an unknown linear circuit from its input/output relationship.