Patent GB-727887-A (GB)
Title: Improvements in or relating to electric code registering and calculating devices
IPC: G06F7/52
Filed: 1950-11-23
Abstract: 727,887. Digital electric calculating-apparatus. SOC. D'ELECTRONIQUE ET D'AUTO-, MATISME. Nov. 23, 1950 [Nov. 23, 1949; May 3, 1950], No. 28728/50. Class 106 (1). An electric circuit for handling series-mode pulse trains representing binary numbers, comprises registering circuits (I-IV), one for each pulse place, an input channel including means for distributing the pulses sequentially to the corresponding registering circuits, and a reading channel including pulse-delay means similar to the distributing means and adapted to deliver, in response to an applied signal, a pulse train into an output channel. A carry-over circuit 13 may be provided whereby, if a reading signal in the form of a series-mode pulse train is applied to the reading channel, a pulse train representing the product of the numbers represented by the registered train and by the reading signal, before being delivered to the output channel, is " corrected,'' e.g. as described in Specification 716,172, pulses of higher amplitude (representing " 2 " or more) being replaced by normal-amplitude'pulses in higher denominations. In the form shown in Fig. 1, a registration-controlling pulse applied to terminal 6 is sent via tappings 4<1>-4<4> on a delay line 5 (each section 5<1>, 5<2>, 5<3> of which provides a delay # equal to a single inter-pulse period) to gate circuits 1<1>-1<4> so that each gate is open to a pulse (representing " 1 ") in a selected place of the input train applied to terminal 2, which pulse switches over the corresponding bi-stable trigger stage I-IV (called " flipflop "). The reading signal (pulse or train) applied to terminal 11 is sent via tappings 9<1>-9<4> on a similar delay line 10<1>-10<3> to gates 8<1>-8<4>, conditioned by the triggers, the outputs of which are connected to a common conductor 12. The pulse trains on 2 and 11 may be applied concurrently. As shown in Fig. 4, the stages I-IV comprise Schmitt trigger circuits of which the normally non-conducting tubes 23 form the output gates 8 of Fig. 1, the pulses on line 10 being of insufficient amplitude to switch over the triggers. Various modifications are described, e.g. the trigger circuits may be of the symmetrical type and the gates 8 separate therefrom, resetting being effected by applying a pulse jointly to all the normally non-conducting tubes (23), and the delay lines 5 and 10 may be combined. The product output train from a calculating circuit 39, Fig. 9, as described above, after passage through the carry-over circuit and a delay line 43, may be regenerated by a tube 44 to which constantly recurring impulses are applied via terminal 45, and applied to a junction 46 from which it may be read off at 47 or sent back to terminal 2 or 11 of the circuit 39 via a further delay and regenerating circuit 50/52 and line 53. The first pulse place in each number-representing pulse train may be used to represent the sign of the number, circuits then being provided to obtain the sign of the product. In Fig. 9, the input and reading pulse trains are applied simultaneously to terminals 2, 11 respectively via terminals 55, 57 and tubes 58, 59 which are rendered non-conducting for the first pulse position by " blocking " pulses sent to terminals terminals 54, 56. The first pulses, if any (representing negative sign) are sent via conductors 60, 61 to coincidence tubes 62, 63 which produce a pulse in their common output circuit only if pulses are applied to both tubes simultaneously. This output pulse is sent together with the pulses on 60, 61 to a network of mixing resistances 64, 65, 66 so that only when a pulse occurs on one conductor and not the other is an effective pulse applied to the control grid of tube 67, the output of this tube being passed through a sign-pulse-place-selecting tube 68 to a delay line 70 and the junction 46. In a modification, the sign is stored on a trigger circuit which may be incorporated in the circuit 39. The control pulses for timing the above operations may be derived from a programme circuit including a pulse-distributing delay line. Specifications 679,390 and 709,707 also are referred to.