1. A method for computation of a remainder of dividing a dividend X by a divisor N when processing a signal obtained from a processing system, the method comprising: controlling, by a processing device: (A) for each i th bit position of an n bit binary representation of the dividend X: when a value of the bit position is equal to 1, outputting, as an output for the bit position, a weight of the bit position, and when a value of the bit position is equal to 0, outputting, as the output for the bit position, a value equal to zero, in which the weights of the i th bit positions respectively are residues of 2 i mod N, wherein i=0, 1,. .. , n−1; and setting the dividend X equal to a sum of the outputs for the respective bit positions; and wherein a value of p is equal to one when (A) is performed a first time, and controlling, by the processing device: (B) when N≦X (p) <2 ┌log 2 N┐ is determined to be true, subtracting N from the dividend X to obtain a final remainder X mod N, in which X (p) is equal to the value of X when (A) is performed a p th time, and when N≦X (p) <2 ┌log 2 N┐ is determined not to be true, performing (A) and then performing (B), in which p is incremented by one each time (A) is performed after (A) is performed the first time, wherein, when (A) is performed a given time, the sum of the outputs for the respective bit positions at the given time (A) is performed is determined by an adder, in which the adder has a bit size according to a value of p corresponding to the given time (A) is performed and is supplied with the outputs for the respective bit positions at the given time (A) is performed.