6. The device of claim 3 , wherein the expansion means includes means for shifting a second subset of the symbols of each word to separate the second subset from a further second subset of the symbols of the word, and means for inserting at least one additional symbol between the second subset and the further second subset.
6. The device of claim 3 , wherein the expansion means includes means for shifting a second subset of the symbols of each word to separate the second subset from a further second subset of the symbols of the word, and means for inserting at least one additional symbol between the second subset and the further second subset. 7. The device of claim 6 , wherein the second subset and the further second subset are separated by a number of memory locations corresponding to the additional symbols to be inserted therebetween plus the additional symbols to be added in the further second subset.