Intermediate signed-digit stage to perform residue to binary transformations based on CRT

A residue to binary converter architecture based on the Chinese Remainder Theorem (CRT) is presented. The conversion from residue to binary is performed in three levels: residue to signed-digit; signed-digit to binary; end-around carry adder/subtracter. By choosing the residue number systems based on (2^m-1, 2^m+1) or (2^m-1, 2^m+1, 2^2m+1) moduli sets, the necessary multiplication operations embedded within the CRT can be replaced by simple shift left operations. The CRT equation is realized by using redundant adder/subtracter blocks in the first level and the carry propagation is totally eliminated. The second level of operation converts the redundant form of CRT to the binary representation. The proposed architecture is free of modulo-M adders. This is achieved by using an end-around carry propagate adder/subtracter in the third level. The two moduli converter was designed and simulated on Cadence