Patent GB-711561-A (GB)
Title: Improvements in or relating to electrical calculating circuits
Inventor: WRIGHT EDMOND PHILIP GOODWIN
IPC: H03M7/08
Filed: 1949-11-28
Abstract: 711,561. Digital electric calculating apparatus. STANDARD TELEPHONES & CABLES, Ltd. Nov. 24, 1950 [Nov. 28, 1949], No. 30435/49, Class 106 (1) Electrical equipment comprises a source of electrical pulses, means for producing in sequence from the source pulse arrangements representing in a first notation numbers which are in the geometric progression of a second notation, an accumulator for totalling such arrangements, means for selecting certain of the arrangements for totalling, and means for applying the selected pulse arrangements to the accumulator. In the described embodiment multi-cathode gas discharge tubes MCT1, MCT4 form the units and tens orders, respectively, of a first accumulator. P pulses applied at the cathode of an associated trigger tube CT3 or CT14 are passed when the starter electrode is made positive by the firing of the right hand tube of a gating pair of co'd cathode tubes CT1, CT2; CT12, CT13. Positive potential applied via a " Start Lead " to the trigger electrode of a tube CT5 causes this tube to conduct and its associated tube CT4 to be extinguished. Thus the trigger tube CT6 is brought to a condition to conduct each P pulse applied at its cathode and step on the associated multi-cathode tube MCT2 continuously. The rise in potential at each cathode of the tube MCT2, when it becomes conducting, is applied to a system of coincidence gates MR10-MR14, MR47- 56, and when it coincides with potential from a conducting cathode of the tube MCT1 or MCT4 a rise in potential at the trigger electrode of the appropriate tube CT2 or CT13 fires this tube and, through a consequent rise in potential of the cathode, causes gating of P pulses to step on the multicathode tube MCT1 or MCT4 concerned until the discharge in the tube MCT2 reaches the "O" cathode; positive potential applied from here to the trigger electrodes of the tubes CT1, CT12, causes the tubes CT2 and CT13 to be extinguished and the supply of stepping pulses to the tubes MCT1 and MCT4 to be cut off. The effect of the coincidence gate system is such that during each cycle of the tube MCT2 the amount registered in the " units " and " tens " tubes MCT1 and MCT4 is detected and this same amount added back into the accumulator so that progressive doubling takes place in the first accumulator. In a second accumulator (Figs. 4 and 5 (not shown)) the coincidence gates include a further control whereby each cycle can be controlled by the successive digits of a binary number, action being suppressed when a binary " O " is controlling the cycle. Thus multiplication can be performed ; or, by starting with unity in the accumulator, a binary number can be converted to an equivalent decimal number. Provision is made for the registering of carry-overs and carry-through-carry which is performed simultaneously in all denominations at a prearranged time in the cycle. Suitable indicators may be connected to the cathodes of the accumulator tubes. Provision for non-uniform systems such as British currency is mentioned. Specifications 692,415 and 711,574 are referred to.