Efficient digital to analog encoding

An important issue in analog circuit design is the problem of digital to analog conversion, namely, the encoding of Boolean variables into a single analog value which contains enough information to reconstruct the values of the Boolean variables. Wegener (1996) proved that [3n-1/2] 2-input arithmetic gates are necessary and sufficient for implementing the encoding function of n Boolean variables. However, the proof of the upper bound is not constructive. We present an explicit construction of a digital to analog encoder that is optimal in the number of 2-input arithmetic gates.