Patent GB-1024927-A (GB)
Title: Character correlation system
IPC: G06F17/15
Filed: 1964-10-21
Abstract: 1,024,927. Comparing digital data; matrix stores. SPERRY RAND CORPORATION. Oct. 21, 1964 [Oct. 31, 1963], No. 43014/64. Headings G4A. G4C and G4M. [Also in Division H3] A character correlation system for testing whether selected character combinations exist in a sequence of characters comprises a store 10, Fig. 1, to hold the sequence or storing of characters, an interrogating circuit 16 capable of simultaneously interrogating all positions of the store for a selected character to generate a match signal corresponding to its position in the store, a coincidence matrix 22 adapted to compare reference signals from 24 with the match signals simultaneously in each of severa different spatially shifted positions and counters 26 adapted to count the appearances of each comparison signal. In the apparatus described there are three stores 10, 12 and 14. Each may contain a sequence of characters so that combinations of characters stored in two or three stores may be found. Column wires, which are the sensing windings of individual positions in each store, are common to the three stores. Storage unit, Fig. 3 (not shown).-Each bit is stored in a unit comprising a pair of thin film cores 38, 40 forming a compact sandwich together with conductors 50, 52, 54, Each core has a preferred magnetic axis P.M.A. along which the magnetism lies in the absence of an external field. The core 38 is the memory element. It is set by the application of an external field by coincident currents on conductors 50 and 52. After the application of the field the magnetism will turn to the nearest direction aligned with the P.M.A. One direction 42 indicates "1" and the other 44, " 0 ". The remanent magnetism of core 38 influences the magnetism of core 40 which is used as a read out device. The flux from core 38 is at right-angles to P.M.A. of core 40. To prevent core 38 being affected by the flux of core 40 the former may be of higher coercivity. If the external field of core 38 is cancelled by a current in the interrogate conductor 52 the magnetization of core 40 aligns itself with the P.M.A. The flux of steering winding 50 aligned with the P.M.A. of core 40 causes the magnetization of core 40 to revert always to the same direction when the external field is removed. Current in the interrogate conductor 52 will either reinforce or cancel the field of core 38. In the first case nothing happens to core 40 and in the second the magnetization aligns itself with the P.M.A. The change in the second case is detected by a sense conductor 54. If core 38 is set to binary " 1 " and a " 1 " signal is applied to interrogate conductor there is not output from conductor 54. Similarly if both are " 0 " there is no output. In the other cases, i.e. where the value set into core 38 and that applied to conductor 52 are different a signal appears on conductor 54. Stores 10, 12, 14, Fig. 2 (not shown).-Each store comprises an array of storage units arranged in ten columns of five. The interrogate conductors are connected through press-button contacts 95-99, 112-116 and 117-121, to switches 90-94, 102-106 and 107-111, which can be set to positive or negative sources according as to whether it is desired to interrogate for " 1 " or " 0." The sense conductors connect all five units in each column and of all three stores. Five-bit coded representations of alphabetic characters are stored in each column of stores 10 and 12. When the interrogate windings are energized to represent a particular character there will be no output from the column wire of any position containing this character whereas all other positions will have at least one different bit and will produce an output. A character match is therefore indicated by no output. The presence of say " A " in store 10 and " B " in store 12 in the same position is indicated by no output leads 77-86 are applied to coincidence matrix 22. Coincidence matrix, Fig. 5 (not shown).-The matrix comprises an array of storage elements 130 arranged in rows and columns. All the elements of a column are set by an output from the corresponding column wire 77-86. All elements of a row are reset by the interrogation signal applied to the row wire. The elements 130, Fig. 6 (not shown), comprise a thin film core 132 with a drive conductor 136 (the column wires) and an interrogate conductor 138 (the row wires) aligned with each other and normal to the P.M.A. The core is first set to " 1 " by a " 1 " signal on conductor 136 and then tested by the reference signal from switches 180-184, Fig. 5. If the test current on the interrogate lead is also " 1 " the core does not change, so there is no output from the sense lead lying parallel with the P.M.A. Likewise if both are " 0 " there is no output. An output appears only when the set value and the interrogated value are different. The magnetization of core 132 is biased by a small steering field to ensure that it rotates in the correct direction when moving from the set to the unset direction and back. The sense wires 165-170 connect elements of adjacent columns in successive rows so that the response of combinations of different column wires can be tested. For example by interrogating rows 1 and 2 the presence of the same character in adjacent positions of the stores 10 or 12 can be indicated. The presence of a selected character is indicated, by the absence of a signal on the corresponding column wire and the associated element 130 remains unset, i.e. at " 0 ". If the row wires 150 and 151 are now given a " 0 " signal all the " 1 " cores will reset but the unset cores will be unchanged. A zero output from sense wire 165 therefore indicates that the selected character is present at positions 1 and 2 of the store being interrogated. The sense wires 165-174 are connected to flip-flops 441-450. Those relating to the last four sense wires 171-174 which link less than five elements may or may not be required and outputs are controlled by switches 520-523. Gates 454-163, one for each flip-flop are enabled by switch 466 to read out the contents of the flip-flops. The row wires are energized by switches 180-184 via common switch 190 and inverters 192-196. The inverters cause a " 0 " signal to be applied when the corresponding switch is set to " 1 ". This compensates for the fact that the presence of a character is indicated by the absence of a signal and an unset condition of the element 130. The presence of a selected combination is indicated by the absence of a signal on a sense wire 165-174. The presence of a sense signal resets the associated flip-flop (previously all set to " 1 " by switch 452) so that those remaining set indicate the presence of a selected combination by an output signal on read-out leads 530-539. Counter bank 26, Fig. 8 (not shown).-For each of the leads 530-539 there is a counter consisting of four serially connected elements 200, each of which is as shown in Fig. 9 (not shown). A thin film core 202 has a drive conductor 206 and a sense conductor 204 normal to the P.M.A. and a word conductor 280 aligned with the P.M.A. The sense conductor has a hairpin portion 203a so that, by crossing the word conductor twice in opposite directions it is prevented from picking up signals when the signal changes in the word conductor. The core is set by the combined action of a signal in the drive conductor 206 either " 1 " or " 0 " and a signal in the word conductor. Either alone is insufficient. The word conductors form the column wires 216- 218, Fig. 8, and the drive conductors form the row wires 224-227. The sense wires 220-222 are connected in series. The row wires are energized in succession by pulse pairs as shown in Fig. 12 (not shown). These are produced by generators 270-273 interconnected by delays and each having two inputs, one of which causes the generator to produce a negative pulse 276 followed by a positive pulse and the other causes the opposite. The sense wires produce a positive pulse when a core in that column switches from " 0 " to " 1 " and a negative pulse when switching from " 1 " to " 0 ". The word windings 216-218 are energized by flip-flops 230-232 which are set via OR gates 234-236 by the signals on leads 530-539. They can also be set by a " Set " switch 238 and reset by a " Clear " switch 244 applying a signal through OR gate 240. Other reset inputs may be applied via AND gates 246 and 248 which are enabled respectively by the " decrement " switch 254 and the " increment " switch. This determines whether counting shall be up or down. The other signals to AND gates 246 and 248 are from the ends of a centre-earth winding of transformer 260. The primary is energized by the sense signal via amplifier 262. The switches 254 and 256 also determine which of the generator inputs shall be energized and consequently the order of the pulses within each pair. An initial value of " 1 " or " 0 " are set into the counter stages by switches 312-315 connected to the row wires and the flip-flops 230-232 are set by switches 238 to produce the word current. The counters count up or down from this value, according to whether switches 256 or 254 are closed. An output 320-322 is taken from the last element of each column which does not store a bit of the number to be operated on. It is used only for read-out purposes. The operation of the counter is as follows: If the flip-flop 230 is set and the switch 256 is closed a value of one is to be added to the value set into the counter. Suppose a value of 5 is entered into the counter, the elements being set to " 101 ". Since switch 256 is closed generators 270 applies pulses 276 and 278 driving the cores towards " 1 " and then towards " 0 ". Combined with the " 1 " signal on wire 216 this would drive the first core to the " 1 " position but since it is already in this position nothing happens. The following pulse 278 switches the core to " 0 " and causes an output on wire 220. This applies a negative s