An encoder encodes data to generate corresponding encoded data. The encoder includes a data processing arrangement for applying one or more encoding processes to the data to generate the encoded data. The data processing arrangement is operable to represent the data at least partially in a set of numerical value symbols, if the data is not already expressed in numerical value symbols. The data processing arrangement is operable to generate intermediate data in which the numerical value symbols are represented by original values and at least one symbol by a modified value with one or more continuum symbols generated by a continuum operator. The one or more continuum symbols modify preceding symbol values to accommodate an extended range of symbols.