GB756234A - Improvements in electronic accumulators - Google Patents

Abstract

756,234. Digital electric calculating-apparatus. INTERNATIONAL BUSINESS MACHINES CORPORATION. March 17, 1954 [March 20, 1953], No. 7752/54. Class 106 (1). A decimal accumulator is characterized by the absence of any carry storage devices, the input pulses being sufficiently spaced in time to permit any carry necessary to occur immediately after the arrival of the pulse necessitating the carry, and before the arrival of the next pulse to be counted. A pulse to be counted, which may arrive on any of a number of parallel denominational channels is fed via a pulse-shaping triode 16 to the transfer electrodes T0-T9 of a multicathode tube G, described in Specification 734,903, and its trailing edge causes the glow, previously established between one of the digitelectrodes D0, D1-D9 and the anode A, to step to the next digit electrode. The arrival of the glow on the D0 electrode causes a rise in potential on a lead 23, which rise causes a negative carry-pulse to be passed from a carry tube 27, via a lead 32, direct to the transfer electrodes of the next higher denomination. A number may be subtracted from the number in the accumulator by first applying a complement pulse to the complement electrodes C0-C9, which causes the number in the accumulator to be replaced by its nines complement, then adding the number that has to be subtracted, and finally applying a further complement pulse. Read out is accomplished by suppressing interdenominational carry and applying ten input pulses to each tube, the differentially timed changes in potential on leads 33 then being representative of the number in the accumulator. The accumulator is initially zeroized by a switch 21. Specification 735,750 also is referred to.