Patent GB-740756-A (GB)
Title: Introduction and extraction arrangement for electronic calculators
IPC: G06F3/08
Filed: 1952-10-03
Abstract: 740,756. Digital electric calculating apparatus. COMPAGNIE DES MACHINES BULL. Oct. 3, 1952 [Oct. 5, 1951], No. 24851/52. Class 106 (1). An equipment adapted to apply at the input of a circulating pulse memory pulses representing, in a given four-component notation, a number expressed in the decimal system and recorded either in a totalizer or in a record card, comprises a coder which emits, during the passage of each storage cell at the memory input, and during the scanning of each of the lines 9 to 1 of the card or totalizer, the numeral of this line represented by pulses in the fourcomponent notation, and an electronic sequence switch adapted to connect the memory input to the appropriate card-sensing or totalizer outputs in the sequence of the denominations of the number to be stored. The invention also concerns the extraction of data from a circulating pulse memory in a similar manner. A simplified form of the apparatus is shown in Fig. 3. Sensing brushes 19 ... 22 explore a perforated record card 23 causing energization of relays 26 ... 29 and transference of their contacts 26a ... 29a as the digit-representing perforations are sensed. Control pulses (see Fig. 3a) constituting the sequence switch are applied to the second inputs 34, 36, 38 and 40 of diode gates in the leads from the sensing circuits and serve to stagger the pulses representing the sensed data in accordance with their columnar positions. At a further diode gate 46, 47 a " coder " 48 supplies groups of pulses representing, in binary series mode, the values of the decimal digits which may be sensed at each point of the machine cycle. Thus the signal train which passes this gate consists of a succession of binary-coded decimal digit signals, differing in phase within each decimal digit period in accordance with the card columns represented, and following a descending order of decimal digits. This train of signals is stored in a pulsecirculation memory consisting of a delay line 51 and a pulse regenerator 52; the memory has a circulation time (in this simplified example) sufficient to accommodate the succession of four decimal digits, each represented by up to four binary pulses. The computing circuits which operate in conjunction with the memory are not shown in Fig. 3, but Fig. 1 shows a diagram including an add/subtract device 5 and a circulating pulse memory 1, 97, 2, 3, 4 in which, by means of gates 6 and 10, the binary-coded decimal number stored therein can either circulate within the path 1, 97, 2, 3, 4, 10 or the path 1, 97, 2, 3, 4, 6, 7, 5, passage through the unit 5 enabling the addition or subtraction of another number applied simultaneously via a terminal 9. By repeating such operations multiplication or division can be performed. Output. Means for extracting data from the memory loop is represented in Fig. 1 by a gate 12 and an extraction device 11. In Fig. 3 an equivalent gate 57 is opened to apply the stored result to a comparator 56 while a succession of binary-coded representations of decimal digits is also supplied to the comparator from the coder 48. The comparator delivers a pulse at its output 58 each time the binary patterns of pulses applied at its input terminals 54, 55 are in agreement and, by applying the pulses I to IV of Fig. 3a to the diodes 60, 62, 64, 66 of a further group of gates, thyratrons 68 ...71 are fired to energize relays 72 ... 75 actuating printing or punching devices in the usual manner. Comparator. A diagram of the comparator 56 is shown in Fig. 4. Identical transformers 80, 82 convert the positive pulses from the inputs 54, 55 into negative pulses at a diode gate 86, so that a timing pulse T5, occurring at the beginning of each binary period, causes the transmission of a positive pulse, via a buffer diode 87, to a gate 89 only when the binary digits appearing simultaneously at the inputs 54, 55 are zero. When simultaneous positive pulses occur a gate 76, 77 is opened and a positive pulse passes a buffer diode 78 to the gate 89. At the first binary pulse period of each decimal digit period a positive pulse is supplied to a terminal 95 which prepares the gate 89 to pass the first coincidence pulse (if present) applied to the input 89a. After passing through a regenerator 90 and a delay element 91 this pulse appears at the input 89b of the gate 89 coincidentally with the arrival of the second pulse (if any) at the input 89a. If four such pulses arrive consecutively, signifying identity between the decimal digits represented at inputs 54, 55, the pulse circulating round the loop 89, 90, 91 survives to arrive at the input 92 of a gate 13 simultaneously with the arrival of the next positive pulse from the terminal 95. This causes a positive output pulse which may be utilized for operating printing magnets &c. as described above. A more detailed form of the apparatus is also described in the Specification, and in addition to the use of a record card for the input data, means for deriving the data from a mechanical totalizer is described. Specifications 710,293 and 730,297 are referred to.