ABSTRACT

In this chapter, a logic optimization method called the transduction method, which was developed in the early 1970s, is described. Unlike the logic synthesizer in two phases described in Chapter 11, we can have logic synthesizers with totally technology-dependent optimization, based on the transduction method, and also can have transistor circuits with better quality, although it is more time-consuming to execute the method. Some underlying ideas in the method came from analyzing the minimal logic networks derived by the integer programming logic design method mentioned in Chapter 9, Section 9.5. The integer programming logic design method is very time-consuming, although it can design absolutely minimal networks. The processing time almost exponentially increases as the number of logic gates increases, and it appears to be excessively time consuming to design minimal logic networks with over about 10 logic gates. Unlike the integer programming logic design method, logic synthesizers based on the transduction method are heuristic, just like any other logic synthesizer for synthesizing large circuits, and the minimality of the transistor circuits derived is not guaranteed, but one can design circuits with far greater numbers of transistors.