Memory storing redundant binary codes and arithmetic unit and discrete cosine transformer using such memory

A memory, which consumes less electric power and has a longer life, stores a redundant binary code produced by replacing each digit of data in binary representation, with a separate 2-bit string allocated to a value which the digit can take. If a value to be output before or after a value is output from the memory is known, a redundant binary representation and a redundant binary code associated therewith are determined such that the number of transitions can be reduced. Thus, a memory which consumes less electric power and has a longer life can be provided.