Abstract :
Some control and computing problems are discussed in which advantage may be gained by encoding analogue quantities into digital form for subsequent processing. A voltage-to-digital converter has been designed for use with an electronic analogue computer in order to combine analogue and digital computation techniques. The system is basically a servo with a digital-to-voltage converter as a non-linear feedback element. A binary register, driven from a 100 kc/s clock pulse, is operated by gates arranged to allow an increasing or decreasing count, dependent on the sign of the error between the voltage input to the converter and the voltage analogue of the number in the register. Functional descriptions of the main parts of the equipment are given, with reference to some of the factors that have been found to be critical. The apparatus is now working, but experience has shown that considerable increase in both speed and accuracy is possible, and modifications which would provide this improvement are described.
