Patent ID: 6233593
Filing Date: 2001-05-15
Classification: H03H

Abstract:
An improved FIR filter based on squaring of the type having an input stage for squaring an input signal, an input accumulator for accumulating the squared input signal, an accumulator stage having T cells for combining the input signal, the squared input signal and the filter coefficients, a first subtractor for subtracting the squared input signal from the output of the accumulator stage and a second subtractor for subtracting a constant equal to the sum-of-squares of the filter coefficients from the output of the first subtractor to produce a filtered output signal, wherein the improvement comprises:means for forcing the input signal to zero for T samples, where T is the number of accumulator cells in the accumulator stage; andmeans for latching the output from the first subtractor as the constant for input to the second subtractor after T zero samples of the input signal have been input to the filter.