Generalized signed-digit number systems: a unifying framework for redundant number representations
Behrooz Parhami · IEEE Transactions on Computers · 1990
Signed-digit (SD) number representation systems have been defined for any radix r>or=3 with digit values ranging over the set (- alpha , . . ., -1, 0, 1, . . ., alpha ), where alpha is an arbitrary integer in the range 1/2r>