1. A method of converting a monotonic sequence of input words to a sequence of digital output words, said method comprising: translating said sequence of consecutively valued input words to produce a range of output words, said translating step producing an output word for each input word, wherein said range of output words is a function of said sequence of consecutively valued input words; locating regions in said sequence of output words in which consecutive input words translate to a common output word; calculating the number of consecutive input words that translate to a common output word in each of said regions; producing an error signal for each output word in said regions, said error signal representing the number of consecutive input words that translate to said output word and the relative location of each output word within said regions; and adding said error signals to said output word corresponding to said error signal.