Patent ID: 6483872
Filing Date: 2002-11-19
Classification: H03H

Abstract:
A method for adaptively filtering a communications signal in a digital filter, the method comprising:running the digital filter with a set of coefficients in response to a run of the digital filter wherein the digital filter comprises a feed forward filter having an input for the digital filter and an output, a feedback filter having an output, a summing node connected to said outputs, and a quantizer connected to said summing node and outputting a signal for the digital filter, wherein each feed forward filter and feedback filter includes a plurality of delay elements and taps for multiplying any delay values from the delay elements by a coefficient contained in the taps, and an update tap and controller in each filter for generating new coefficients in response to error signals generated by comparing the output of the summing node to a prestored or preprogrammed signal within respective update taps; determining whether an output from the digital filter using a set of coefficients is equal to a selected error level; adjusting the coefficients within the set of coefficients until the output from the digital filter using the set of coefficients are equal to the selected error level in response to a determination that the output from the digital filter using the set of coefficients is unequal to the selected error level; storing the set of coefficients in a memory to form a stored set of coefficients; and loading the stored set of coefficients into the digital filter from the memory in response to subsequent runs of the digital filter while also operating in a selected plurality of modes of operation, wherein said modes of operation are selected responsive to the set of coefficients being unable to meet first and/or second error levels and operating until selected sets of different coefficients meets first and/or second error levels, wherein after an initial run by testing all â€œNâ€  sets of coefficients stored in the memory for â€œMâ€  programmable iterations, when any sets of coefficients satisfy an acceptable threshold, then using those coefficients as the initial coefficients values, and if not, then using a default set of coefficients or the last tested set of coefficients wherein N and M are integer.