GB1145916A - Signal transmission system in data processing devices - Google Patents

Abstract

1,145,916. Circuit assemblies. SCIENTIFIC DATA SYSTEMS Inc. 6 June, 1966 [9 June, 1965], No. 25161/66. Heading H1R. In a data processing system the wires interconnecting the active and passive circuit elements run in the proximity of one or several conductive plates to which the elements are also connected. In the embodiment of Fig. 1 a frame 10 receives a plurality of circuit modules 11, 12, 13 each module comprising a printed circuit network supporting a plurality of circuit elements interconnected to form a logic circuit module. Connector pins of the modules traverse in pairs small slots in the electrically conductive plate 25. Pins 15 and 18 of module 11, pin 16 of module 12 and pins 17 and 19 of module 13 are connected by short connecting wires to the plate 25 which is at ground or reference potential. The modules are interconnected by wires 26, 27, 28 connected to the appropriate pins and insulated from each other. Since the signals transmitted between the modules have a high pulse rate frequency the connections made constitute high frequency transmission lines. A voltage source for driving the modules, Fig. 2 (not shown), has one terminal connected to the ground plate 25 and its other terminal connected via feeder cables to the various pins of the modules. The signal transmission characteristics from module to module can be further improved by including a conducting plate 45 in each module, Fig. 3. Each module comprises an insulating ground plate 40 carrying on one side elements 41, 42, 43 the connecting wires of which are connected to etched conductors 44. The plate 45 is connected to the etched conductors 44 through holes in the ground plate 40 at points where ground potential is to be applied by means of pins such as 15 of Fig. 1. The ground plate 25 and conducting plate 45 have an effective capacitance relative to the cable connections which offsets or balances any inductance provided by curvatures in the cables and/or etchings and also act as shields.