1. (b)
Figure 3.2: Two types of multiplier: (a) Scaled addition and (b) Scaled subtraction in SC
where var(pˆi) = σ2 (pˆi) , i = 1, 2, σ (pˆi) calculated as (1.6).
Besides, a stochastic scaled subtraction can be carried out with a small change as illustrated in Fig.3.2b.
In this configuration, a NOT gate is used to perform the subtrahend p2. It can be writen as
pout = s.p1 + (1 − s).(1 − p2) (3.5)
Note that this operator only works for the bipolar representation. Therefore, by assuming p1b , p2b , poutb are the bipolar formats corresponding to the unipolar ones p1, p2, pout, (3.5) can be become the expected scaled subtraction
poutb = s.p1b − (1 − s).p2b . (3.6)