Digital-Analog-Wandler

摘要

846,381. Electric selective signalling systems. ELECTRIC & MUSICAL INDUSTRIES Ltd. Oct. 25, 1956 [Nov. 4, 1955], No. 31535/55. Class 40 (1). - As described, the digits of a 5-digit decimal number are received successively at terminals A1-A4, highest denomination first in binarycoded decimal form (e.g. from a punched-tape reader) are staticized on relays-one digit in each of five " relay operating units "-are each used to select one of ten tappings of a transformer to produce A.C. potentials having amplitudes representative of the five digits at terminals U, T, H, Th and Tt, which potentials are both scaled by factors 10-4, 10-3, 10-2, 10-1 and 1 respectively and summed by means of series connected 1-10 transformers TR2, TR3, to produce, from the secondary winding of transformer TR2 a single final output potential on a terminal A5 representative of the staticized decimal number. Each " relay operating unit "-one only being shown in detail-comprises four relays and is so arranged that on the application of a negative pulse to its normally positive control terminal A6-A10 its four relays assume conditions corresponding to the potentials then present on terminals A1-A4. These conditions are maintained by the relays until changed by a further negative control pulse. Thus to staticize the incoming decimal digits, the terminals A6-A10 are pulsed negatively in succession in synchronism with the receipt of successive digits. The output of the converter may be used in a servosystem, as a command, to position, for example, a machine tool, the command being applied to a differential amplifier SA together with a signal, such as obtained by a brush W moving over contacts SW, representative of the position of the machine tool. Specifications 726,037, 796,993 and 802,472 are referred to.