1. In an apparatus for processing signals in the form of digital words, comprising (a) filtering means having an input terminal for receiving a sequence of input digital words, and an output terminal for supplying a sequence of filtered words; (b) selection means having input and output terminals, said selection means input terminal being connected with the output terminal of said filtering means, said selection means being operable to omit predetermined words from the sequence thereof and for supplying a reduced number of digital words to said selection means output terminal; and (c) output means connected with said selection means output terminal for acting upon the reduced number of words; the improvement which comprises (d) monitoring means connected with the input terminal of said filtering means for determining if the input digital words have a characteristic similar to the filtered words; and (e) bypass means operable by said monitoring means when said monitoring means determines that an input digital word has a characteristic similar to a filtered word for causing the input digital word to bypass said filter means and thereby remain in the non-altered condition.
1. In an apparatus for processing signals in the form of digital words, comprising (a) filtering means having an input terminal for receiving a sequence of input digital words, and an output terminal for supplying a sequence of filtered words; (b) selection means having input and output terminals, said selection means input terminal being connected with the output terminal of said filtering means, said selection means being operable to omit predetermined words from the sequence thereof and for supplying a reduced number of digital words to said selection means output terminal; and (c) output means connected with said selection means output terminal for acting upon the reduced number of words; the improvement which comprises (d) monitoring means connected with the input terminal of said filtering means for determining if the input digital words have a characteristic similar to the filtered words; and (e) bypass means operable by said monitoring means when said monitoring means determines that an input digital word has a characteristic similar to a filtered word for causing the input digital word to bypass said filter means and thereby remain in the non-altered condition. 3. Apparatus as defined in claim 1, wherein said bypass means comprises a data selector circuit arranged to receive as inputs both input digital words and filtered words, said data selector circuit being operable to output one of said inputs under the control of the monitoring means.