Patent GB-767981-A (GB)
Title: Improvements relating to apparatus for transferring electric data pulse trains between synchronously operating devices
IPC: G06K7/016
Filed: 1954-06-16
Abstract: 767,981. Electric digital-data-storage apparatus. MONROE CALCULATING MACHINE CO. June 16, 1954 [July 24, 1953], No. 17681/54. Class 106(1). In apparatus for transferring electrical data pulse trains between synchronously-operating devices which may be out of phase by one pulse time, a storage element is successively set to represent pulses of the leading device pulse train, and is sensed for producing pulses in accordance with the settings for entry in the lagging device. Where the devices may be out of phase by n(>1) pulse times, n sequentially operated storage elements may be provided. In the magnetic storage system shown in Fig. 1, a motor 25 drives a master drum A and, through a mechanical coupling 26, a second drum B. Each drum has channels in which data is recorded in binary form (" 1 " and " 0 " being represented by magnetization in opposite directions), and associated magnetic readrecord heads 28 are connected through selection circuit 36 and a relay contact 38 to either a read circuit 34 or record circuit 32. Further channels X, Y provide timing signals. The signals obtained from X, one for each binary digit period, actuate a pulse generator 30 which produces trains of pulses A A  and R A , or A B  and R B , Figs. 1 and 2, which time reading and recording respectively. The A-pulses step on a counter 29 from which time-period-defining outputs 33 are obtained through matrix 31. To enable data read from drum A to be recorded on drum B, the circuit 34 for A includes means to compensate for lack of synchronism between pulses A A , A B , the timing being so arranged that the latter pulses always lag. The binary signals from A are applied to amplifier 40 whose output PB A , Figs. 1 and 2, is applied directly and through inverter 42 respectively to pentode gates 48, 52 controlled by pulses A A . The signals PB A  have a positive or negative portion coinciding with A A  for " 1 " or " 0 " respectively, to cause pentode 48 or 52 to conduct and set triode trigger pair or " nip-flop " 50 into one conductive condition or the other. The outputs I A  and I<SP>1</SP>A of the flip-flop, which are at a relatively high potential for " 1 " and " 0" respectively, are applied to pentodes 60 controlled by pulses A B  to set a further flip-flop 62 in time with the latter. Thus, if pulses A B  occur at times x, y or z, Fig. 2, the setting of flip-flop 62 to represent a " 1 " and produce a high output I B  will be delayed a corresponding period relative to the corresponding setting of flip-flop 50 (output I A , Fig. 2). This output I B  causes circuit 32 controlled by pulses R B  to record a " 1 " on drum B. The circuit of Fig. 3 can compensate for larger time lags and is controlled alternately by odd and even pulses A A0 , A AE  and A BO , A BE  obtained from circuits 69, Fig. 1. The drum output PB A , Fig. 3, and its inverse on line 46 are applied to pairs of pentodes 90, 92 controlled by A A0 , A AE  to set up flip-flops 94, 102 respectively whose outputs control the setting of flip-flop 98 in time with A BE , A B0 . Thus, if the A B0 , A BE  pulses occur at times indicated by broken lines S, T, Fig. 2, respectively, one and nearly two digit periods later than in the full line position, the output Iy from 98 is correspondingly delayed with respect to the output IT of 102. In the compensating arrangement of Fig. 6, the pulses A A , A B  are further divided into A A1 -A A4 , A B1 -A B4  by applying pulses A A0 , A AE  and A B0 , A BE  to alternate magnetic cores of shift registers 148, 149 each having a single core in the " 1 " state. The output from drum A is applied by playback circuit 178, in the form of negative " 1 " representing pulses from a resting level of +20 v., to windings 166<SP>1</SP>-166<SP>4</SP> on the cores of register 148. When a negative pulse A A1 -A A4  is induced in a winding at a time when a " 1 " pulse is received, a corresponding condenser 174<SP>1</SP>-174<SP>4</SP> is charged through a diode 168<SP>1</SP>-168<SP>4</SP>. The condenser is subsequently discharged by the corresponding positive pulse A B1 -A B4  induced in winding 170<SP>1</SP>-170<SP>4</SP> on a core of register 149, thus producing on line 180 a negative output pulse which, through differentiating circuit 190, inveiter 192 and circuit 194, sets flip-flop 196 to its " 1 " condition, the flip-flop being reset by pulses A B  applied through gate 200. A system for synchronizing two storage drums with an associated electronic computer (Fig. 4, not shown) employs two compensating circuits like that of Fig. 3, and a fixed delay circuit, e.g. a shift register. Reference is made to synchronizing data obtained from other devices, e.g. magnetic tapes, and to the use of the quinary (instead of binary) system.