Patent GB-700691-A (GB)
Title: Improvements in or relating to an electronic multiplying apparatus
IPC: G06F7/62
Filed: 1950-12-06
Abstract: 700,691. Digital electric calculating-apparatus. INTERNATIONAL BUSINESS MACHINES CORPORATION. Dec. 6, 1950 [Dec. 8, 1949], No. 29864/50. Class 106 (1) In an electronic multiplying apparatus, pulse trains having different recurrence frequencies (each ten times the next lower one), for effecting multiplication of the multiplicand by different orders of the multiplier, are passed through coincidence circuits to a result register under control of sequencer circuit means synchronized with the cyclic operation of a multiplier receiving device. General arrangement.-The apparatus described is generally similar to that of Specification 705,574. An oscillator 10, Fig. la, supplies pulses F3, KF3, 180 degrees out of phase, to leads 11, 12 respectively. The pulses KF3 are sent to a step-down circuit 14 comprising four seriesconnected hard-valve trigger pairs with a feedback arrangement (similar to that used in the orders of the result register of Specification 705,574), such that output pulses F2, KF2 of onetenth the recurrence frequency appear on leads 15, 16. Pulses KF2 are sent to a similar stepdown circuit 18 to produce pulses Fl, KF1, Fig. 4a, of one-hundredth the frequency of F3, KF3, on leads 19, 20. Pulses F1 are sent to a stepdown circuit 22 comprising five series-connected trigger pairs to produce pulses A and C, D, Fig. 4a, of one-half and one-thirty-second the frequency on leads 23, 24, 25. Pulses F1, 2, 3 are sent also through gates 51U, 121T, 137H, which correspond respectively to the units, tens and hundreds orders of the multiplier, and gates 37U, 39T, 41H, controlled by the multiplicand unit as described in Specification 705,574, to the first three orders of the result register RR, Fig. 1b. Tens transfer is controlled by pulses KF1, 2, 3 sent to gates 49CU, 119CT, 135CH. The multiplicand unit Mc is normally supplied with negative pulses from a gate 31 controlled by positive F1 pulses and conditioned by a trigger circuit Tmc. Switching of this trigger to supply positive pulses from gate 33 controlled by negative KF1 pulses, and thus start the sequential switching of the digit-representing triggers of the unit Mc, is effected by a positive C pulse sent through one of the pairs of gates 53U, 79U, 123T, 125T, and 139H, 141H, corresponding respectively to the three orders of the multiplier. In the present apparatus, the multiplier unit Mp is similar to the unit Mc, comprising only one set of digit-representing triggers, and has an associated trigger Tmp and gates 65, 67 (controlled by C and D pulses), corresponding to Tmc, 31, 33, respectively. The sequence of operations is controlled by a unit S comprising triggers S1TS3T, corresponding to the three orders of the multiplier, and a control trigger S4T. Operatian.-When the multiplicand and multiplier have been manually set on switches as described in Specification 705,574, a switch 45 is opened and applies a voltage to triggers SIT, S4T to switch them to the operative condition. Trigger S1T applies a potential through an isolating tube (not shown) over lead 48 to condition gates 49CU, 51U and 53U. Trigger S4T similarly conditions a gate 55 so that the next negative A pulse switches trigger Tmp and a trigger 62 and starts a cycle of the multiplier unit Mp. the digit-representing triggers being successively switched by negative C pulses applied to gate 65. When the trigger corresponding to the units multiplier digit is switched a potential is applied through the corresponding set switch over lead 78 to condition gate 79U. The next positive C pulse switches trigger Tmc through gates 53U, 79U to start a cycle of the multiplicand unit Mc. One of these cycles occurs for each trigger of the unit Mp still to be switched, and during each cycle the multiplicand is entered once in the register RR in a manner similar to that described in Specification 705,574. When the last or one-representing trigger of unit Mp is switched a potential is sent over lead 116 to trigger Tmp such that it is reset by the next negative KF1 pulse on lead 117 and conditions gate 67 so that the next positive D pulse causes a negative pulse to be sent over line 70 to restore all the multiplier triggers. This pulse is also sent through a gate 73, conditioned by the trigger 62, so as to reset trigger S1T which then applies a switching pulse to trigger S2T. Similar operations then occur for the tens multiplier digit, but due to the higher frequency of pulses F2, . KF2 applied to gates 121T, 119CT, the multiplicand is entered into the result register ten times during each cycle of the unit Mc. At the end of the next cycle of multiplier unit Mp, trigger S2T is reset and switches over trigger S3T to effect multiplication by the hundreds multiplier digit, the multiplicand being entered one hundred times during each cycle of unit Mc under control of pulses F3, KF3. At the end of the third cycle of unit Mp, trigger S3T is reset and resets trigger S4T which deconditions gate 55 and resets trigger 62. The apparatus is then in the starting condition.