Digit-serial transversal filters

Abstract

One type of transversal filter using digit-serial signals in its operation comprises a to-digit-serial converter for converting a succession of input data words received at its input port each to a respective succession of m-bit-wide digits supplied from its output port in order of progressively greater significance, m being a positive plural integer; a clocked delay line having an input tap connected for responding to the m-bit-wide digits supplied from the output port of the to-digit-serial converter and having at least one further tap for supplying a respective tap signal; and means for performing a weighted summation of the input signal to the clocked delay line and each tap signal from the clocked delay line, to generate a filter response in digit-serial format. Another type of transversal filter, which uses digit-serial signals in its operation, comprises a plurality, p in number, of parallel-to-digit-serial converters, each for generating a respective m-bit-wide digit-serial data stream by converting n-parallel-bit words in an input signal to the digital filter, m being a positive integer and n being the product of m and p; a plurality of tapped delay lines having respective input taps connected from respective ones of said parallel-to-digit-serial converters and each having at least one further tap; means for generating p different phases of filter response in digit-serial form by weighting and summing digital signals taken from respective taps on ones of the p tapped delay lines; and p digit-serial-to-parallel converters for converting, on a cyclic basis, the different phases of filter response to parallel-bit words in an output signal from the digital filter.