Patent GB-836806-A (GB)
Title: Electronic multiplier
IPC: G06F7/62
Filed: 1956-06-27
Abstract: 836,806. Electronic mutiplying-apparatus. TOLEDO SCALE CORPORATION. June 27, 1956 [July 1, 1955 ; May 28, 1956], No. 19949/56. Class 106 (1). An electronic computer comprises a multiplicand pulse generator which, in response to each pulse of a multiplier pulse generator comprising a series of single cycle oscillators arranged to operate in sequence, generates an invariant series of pulses and selects from each series, pulses corresponding to the value of the multiplicand which are transmitted to one or more decades of an electronic counter, and control pulses which are applied to reset carry storage means connected between the counter decades. First embodiment.-In the arrangement shown in Fig. 1, a 4-digit multiplier is set on switches 2, 6, 10, 14 and a 4-digit multiplicand on switches 33-36 corresponding to the units multiplier digit, and on further switches (such as 56, 70, 78 ganged to 33) for the higher multiplier digits. Each switch 2, 6, 10, 14 selects one of ten decimal-digit-representing inputs 0-9 on a multiplier pulse generator 3, 7, 11, 15 which, when a pulse is applied to an input of a given digit value, produces a corresponding number of pulses at its output. Thus, when a start pulse is applied from lead 1 to switch 2 and generator 3, a number of pulses equal to the units multiplier digit appear on output 4. For each such pulse, a multiplicand pulse generator 20 produces, through matrix 30, 1 to 9 pulses on respective output leads 31 connected to the contacts of switches 36-33, whereby numbers of pulses corresponding to the multiplicand digits appear on switch output leads 37, 45, 46, 48 and are applied, via amplifier 38 and amplifiers in carry storage circuits 41, .47, 48 respectively to the first four stages of decimal product counter 40 ; the generator 20 subsequently supplies successive pulses to leads 25-28 for resetting carry storage circuits 41, 47, 49, 52 and transferring any stored carries to the next higher denominations. The multiplicand is thus added into the counter 40 a number of times corresponding to the units multiplier digit. After the last pulse on output 4, the generator 3 supplies a pulse via lead 5 to switch 6 to cause similar operations for the tens multiplier digits, the outputs from switches 56-59 and the carry-storage-resetting outputs from generator 53 being connected to appropriate higher denominations of the counter 40. The generators 7, 11, on completing their operation, similarly supply pulses on leads 9, 13 to effect multiplication by the higher multiplier digits. The product accumulated in counter 40 may be indicated e.g. by neon tubes. The counter may be reset by a pulse on lead 93. Product counter; carry storage circuits.-A carry is stored in a bi-stable trigger circuit including double triode 310, Fig. VI, which normally conducts on its right-hand side and is switched over by a negative carry pulse from the associated lower counter stage on lead 330. When the trigger circuit is reset by the trailing edge of a positive carry-storage-resetting pulse on lead 335, a positive pulse is applied from anode 315 to the grid of amplifier 299 thus producing a negative output signal which is applied to the next higher counter stage. The multiplicand digit - representing pulses are applied to amplifier 299 via lead 290 and rectifier 293. Each counter stage, such as 39, Fig. 1, comprises four cascade-connected bi-stable trigger circuits with feedback connections (not described in detail) to produce a count of ten. Pulse generators.-Each, multiplicand pulse generator (such as 20, Fig. I) may comprise cascade-connected blocking oscillators each including a triode 230, Fig. V, having its anode and grid inductively coupled through a transformer 235. Each oscillator, when triggered by a positive pulse applied to input condenser 244, or coupling condenser 245 from a preceding oscillator, goes through a single cycle during which a positive voltage appears across its cathode resistor such as 234. The first nine oscillators have their cathodes connected in'four groups, whereby 2, 4, 2 and 1 output pulses respectively are produced on corresponding output leads 246, 249, 251 and 253 and applied to diode matrix 247 which so combines these outputs as to supply 1 to 9 pulses on the oorrespondingly marked leads (31, Fig. I). The ninth to twelfth 'oscillators supply the carry-storageresetting pulses on leads 254 and 258-260. Each multiplier pulse generator (such as 3, Fig. I) may also comprise a chain of blocking oscillators each connected to one of the inputs (0-9) whereby the effective length of the chain depends on the input selected. Alternative pulse generator circuits are described comprising transistors or one-shot multivibrators. Alternative embodiments.-An alternative arrangement (Fig. II, not shown) employs only a single multiplier and multiplicand pulse generator the selection of multiplier digits in turn and corresponding denominational selection in the product counter being effected by contacts of a stepping relay whose solenoid is in the plate circuit of a thyratron (Fig. III, not shown), or by an electronic stepping circuit and an array of triode gates (Figs. X and XI, not shown); in the latter case, all of the carry storage circuits are reset after each multiplicand entry. Reference is made also to the use of notations other than decimal, and to the production by a single multiplier pulse generator of a number of pulses equal to the numerical value of the multiplier, where the multiplier is obtained as a reading on a graduated scale e.g. of a weighing machine.