Patent GB-784513-A (GB)
Title: Electronic commutator
IPC: H03K17/54
Filed: 1954-04-01
Abstract: 784,513. Digital electric calculating-apparatus. INTERNATIONAL BUSINESS MACHINES CORPORATION. April 1, 1954 [April 6, 1953], No. 9572/54. Class 106 (1). An electronic commutator comprises a first chain of electron valve trigger elements, means initiating sequential individual operation of said elements, a second chain of electron valve trigger elements connected to one of the elements of said first chain and driven individually in sequence by the operation of said one element, means for interrupting said sequential operation of all the elements of said first chain, but after operation of said one element, and means for initiating a new sequential operation at or before said one element, whereby said second chain is driven at time intervals which are sub-intervals of the time of operation of all of the triggers of said first chain. The invention is described as a modification of the calculator of Specification 673,759 in which calculations are controlled by a Program Ring consisting of 20 cascade-connected Eccles- Jordan triggers 12-31, Fig. 1B, which is advanced one step for each cycle of a Primary Timing Ring consisting of 26 triggers labelled " step 1," " step 2," " delay 1," ... delay 3," and " step 3 " to " step 23," there being a connection between " step 2 " of the Primary Timing Ring and the Program Ring via a lead 210 and an amplifier 211 so that each time " step 2 " goes " on " the Program Ring advances one step, the modification being that the output (terminal 7) from trigger " delay 3 " instead of going direct to the adjacent trigger " step 3 " is fed via an inverter 401 to one input of two " and " gates 403, 408 (the terminal 7 of gate 403 being internally capacitively coupled to terminal 6) which are inversely controlled by the two outputs from a " Skip- Suppress " trigger 415, and thence either to "step 2 "-if gate 403 is open-or to "step 3 "-if gate 408 is open-and, thus depending upon the state of the Skip-Suppress trigger the Primary Timing Ring either makes a complete cycle or reaches " delay 3 " and returns to " step 2." The Skip-Suppress trigger can be turned " on "-when " delay 3 " feeds back to " step 2 "-by either a " Skip trigger 432 or a " Suppress " trigger 430 which together control trigger 415 via an " or " gate 426. The Suppress trigger 430 is set " off every time " delay 1 " goes " on " (lead 447, inverter 446 and lead 445) and is set " on " at the time when " delay 2 " goes " on " if an " and " gate 451 is opened by a positive suppress voltage, if present, on lead 454. Thus if it is required to suppress say stage 10 of the program, i.e. if it is required that when the Program Ring reaches stage 10 it will advance to stage 11 without waiting for the Primary Timing Ring to perform a full cycle, then program hub 10 would be plugged to the " suppress no test " socket and then the Primary Timer would make 9 complete cycles and on the 10th it would proceed only as far as " delay 3 " and then return to " step 2." It is possible, though not described in detail, to make the suppression of a particular stage conditional upon a balance taken at the preceding stage, in which case one of the sockets 485, 487 is used. The Skip trigger can only be set " on " if the Suppress trigger is " off " in which state the Suppress trigger opens an " and gate 507 which allows a pulse from " delay 3 " via lead 510 to pass through to open a " skip on " gate 501 which can then pass a skip signal, if present, from a socket 503, to set the trigger 432 " on." Once the Skip trigger is set " on " it will not go " off " until a positive voltage is applied to a " skip off " socket 518. Thus to skip several stages, say stages 10 to 15, program hub 10 will be plugged to "skip on" socket 503 and program hub 15 to " skip off " socket 518. Since the Suppress trigger exercises a stronger control than the Skip trigger a skip of, say, from stage 10 to stage 15 or a mere suppression of stage 10 can be made conditional upon a balance taken at stage 9. For this particular example, program hub 10 would be plugged to both the " skip on " socket and to one of the conditional suppress sockets 485, 487. Specification 750,259 also is referred to.