Abstract: Between digital data signals, which are expressed using a notation system of three digit symmetric binary numbers (named “HEN2”), and analog signals, at least one way, mutual, or other conversions are made. Three digit symmetric binary numbers (HEN2), are a combination of signals in which at least one of two adjacent digits, at any digit position of one or more digits of 2-based three digit redundant binary numbers with one signal of three digits {n, o, p} expressing a value {−1, 0, 1} as a one-digit signal, is a signal “o” expressing zero. Thus three digits {−1, 0, 1} are used instead of the two digit {0, 1} binary system used in conventional A/D or D/A converters.

Abstract: HEN2, which is a combination of signals in which at least one of two adjacent digits at any digit position of one or more digits of a 2-based three digit redundant binary number with one signal of three digits {n, o, p} each expressing value {−1, 0, 1} as a one-digit signal is a signal “o” expressing zero, is handled as one set of notation, not as a subset of the three digit redundant binary number.

Abstract: A central processing unit and a digital data processing system for performing arithmetic processing of numbers that are not presented using traditional 10 radix signed digits 0, 1, 2 . . . 9. The central processing unit and digital data processing system of this invention are configured to process numbers that are from a set of digits {X.sub.1, X.sub.2 . . . X.sub.2n+1 } wherein each of these digits represents a number between -n, . . . -1, 0, 1, . . . n such that n is an integer and n.gtoreq.1. Thus, for any number that comprises more than one digit the most significant digit represents both magnitude and positive/negative state of the number and the remaining least significant digits each have a radix of (2n+1).