ANALOG ADAPTIVE EQUALIZER AND METHOD

摘要

An analog adaptive equalizer is disclosed. The analog adaptive equalizer provides convergence of an error signal by decoupling the error canceller, the automatic gain control and the filter to provide truly adaptive error minimization. The invention includes an automatic gain control (AGC) circuit for providing broadband amplification of an input signal to generate an AGC output signal, a filter for receiving the AGC output signal and providing high frequency signal conditioning to generate a filter output signal, an error detection circuit for generating an error signal representing the difference between the filter output signal and an expected output signal and a calculator for receiving the error signal and providing a gain correction signal to the automatic gain circuit to adjust the gain of the automatic gain circuit and a filter control signal to adjust the filter range of the filter, the gain correction signal and the filter control signal being used to cancel the error signal. The calculator further comprises a first in, first out buffer for providing a history of the expected output signal to the calculator. The filter may have a fixed direct current (D.C.) response and a transfer function according to formula (I), where omega 0 and Q are fixed and A is a variable. The present invention is that the filter control signal is a signal to adjust the value of A. The output of the filter changes monotonically as a function of the filter control signal. The error detection circuit includes a slicer for slicing the filter output signal to generate a sliced signal having the expected output signal and a subtracting circuit for subtracting the filter output signal from the sliced signal to generate the error signal.