Patent GB-698834-A (GB)
Title: Improvements in apparatus for converting an electrical representation of a number from the binary to the denary scale of notation
IPC: H03M7/08
Filed: 1951-06-07
Abstract: 698,834. Digital electric calculating-apparatus. SOC. D'ELECTRONIQUE ET D'AUTOMATISME. June 7, 1951 [June 7, 1950], No. 13564/51. Class 106 (i). Apparatus for converting a number represented in the binary scale by a binary pulse train of decreasing order into the electrical representation of the same number in the denary scale, comprises a pulse counting chain of a step-by-step advancing type, and means for causing the counting chain, upon every occurrence of an impulse moment in the train, to advance by one step if a voltage pulse is present at that impulse moment, and then whether or not a voltage pulse is present at that moment, to advance to the position recording double the value recorded by the previous advancement. The bi-stable devices 30 ... 39, Fig. 2, are preferably hard-valve trigger pairs having an " actuated " condition and a " rest " condition and are arranged so that only one stage can be in the actuated condition at any time; initially, stage 30 is in the actuated condition and all the others in the rest condition. The binary series-mode pulse train which is arranged in descending order with the highestvalue pulse leading, is applied at the terminal 80, and auxiliary pulses are applied at the terminal 60. A starting voltage is applied at a terminal 50, and when the first pulse in the binary-coded train appears at the connection 70, stage 30 is flipped to the " rest " condition and delivers an output pulse which flips stage 31 to the " actuated " condition and causes a further pulse, of a polarity unsuited to actuate the next counter stage, to render the transfer stage 61 conductive and allow an auxiliary pulse, slightly delayed in relation to the binary code pulse, to pass through and actuate the counter stage 32. Thus the first binary digit has been (i) registered and (ii) doubled, and now (iii) the next digit must be added. Assuming the second binary digit to be another " one," a second pulse entering at the terminal 80 finds the stage 32 in actuated condition and flips it over to rest condition. As before an output pulse results which flips the next stage 33 to the actuated condition and this, in turn, produces a pulse suitable for gating an auxiliary pulse through transfer stage 63 to actuate the counter stage 36. A reading-out operation at this stage would detect a voltage on the result line 46 representing the digit " 6 " (=110 in binary form). The decimal registration is built up by this process of repeatedly doubling and adding the next binary digit, the process being continued into higher decimal denominations by tens transfer arrangements. In an alternative embodiment, the auxiliary pulses entering at the terminal 60, Fig. 6, render all the transfer stages 61 ... 69 conductive to pass any suitable pulse from the stages 30... 39. Delay devices 141 ... 144 prevent the triggering pulses which pass via a transfer stage from coinciding with the pulses of the binary-code input train. Series-mode binary pulse trains arranged in ascending order with the lowest-value pulse leading, can be reversed by a circuit comprising an artificial delay line made up of sections each having a delay time equal to two binary pulse periods. Tappings between the sections include gating devices which are opened in succession to pass successive binary pulses into the delay line at points progressing in the same direction as the pulse train which thus becomes reversed or inverted.