These notes from special intensive summer programs on Analog-Digital conversion held at MIT from 1956-1957 focus on problems created when digital equipment is linked with physical systems. A "language" problem arises, for the language of the information-processing equipment is digital and the language of communication in the rest of the system is nearly always in the form of electrical signals or mechanical displacements analogous the the physical parameters involved. Thus, there is a need for devices to perform the language translation. Devices taht perform analog-to-digital conversion are called coders, and devices that perform digital-to-analog conversion are called decoders.The subject matter is divided itno three parts. The first part pertains to systems aspects of digital information processing that influence the specifications for analog-to-digital and digital-to-analog conversion devices. In the second part, a detailed engineering analysis and evaluation of a variety of conversion devices is presented. The third part is devoted to a case study based on development work done at the Servomechanisms Laboratory of the MIT Department of Electrical Engineering.
