Patent GB-838787-A (GB)
Title: Improvements in or relating to signal translating apparatus
Inventor: BIRD RAYMOND
IPC: G06F3/08
Filed: 1956-03-05
Abstract: 838,787. Digital electric calculating apparatus. INTERNATIONAL COMPUTERS & TABULATORS Ltd. March 1, 1957 [March 5, 1956], No. 18335/58. Divided out of 838,786. Class 106 (1). A signal translating device receiving a serial pulse train consisting of a plurality of characterrepresenting pulse groups and operating a parallel output device accordingly comprises a register for storing representations of complete pulse groups successively in a plurality of repetitive cycles, a second register for storing in succession each possible character representation, means operable in each cycle to compare all the character representations stored by the first register with the representation stored by the second register and to generate an output signal on detecting equality, and means for distributing the output signals to a plurality of output channels. In a first embodiment binary-coded decimal digits represented by series-made pulses at an input device 1 are passed into a shifting register 2 which holds one decimal digit at a time. A similar fourbinary-stage register 5 stores a decimal digit starting with " 9 and counting down through " 8, 7 ... 1, 0 " in synchronism with the movement of type or other output devices and at each fourth stepping pulse from a source 13 the contents of registers 2 and 5 are compared by a coincidence gate 4. All the decimal digits of the number entered at the input device 1 are compared in succession with the same decimal digit registered in the counter 5 and, whenever agreement occurs a signal is sent via a diode matrix 15 to the appropriate denomination of the output equipment. A counter 12 fed by the clock pulse source 13 and supplying the coincidence-testing pulse on line 11 at every fourth shift pulse, also supplies to the matrix 15 a signal on one of the lines 16 in correspondence with the denomination which is being examined in the register 2. This signal determines to which of the output lines 17 the agreement signal from the coincidence gate 4 is to be delivered. The firing of a gas tube by this pulse and the subsequent control of synchronized print or punch magnets by those gas tubes which have been fired is described with reference to Fig. 2 (not shown). The closure of contacts 6 under control of the output equipment causes a pulse to be sent via trigger circuits 7 and 9 to the counter 5 reducing the digit registered therein by unity, whereupon all the digits of the data from the input device 1 are now compared successively with this digit, and so on. A similar arrangement above the register 2 comprising a counterregister 36 and coincidence gate 35 is used for reading out non-decimal items such as pence, Indian currency, or items in other non-uniform systems, or may be adapted for zone signals in reading out alphabetical characters. A device 60 enables characters to be read out in parallel binary-decimal or other four-point codes. Comparing device.-Each stage of the coincidence gate 4 comprises a double triode 61, 62, Fig. 3, with grids connected through resistors 63 to the respective anodes of the trigger pair forming the corresponding stage of the register 2, and cross-connected through further resistors 63 to the anodes of the corresponding trigger pair in the counter 5. The cathode of valve 61, 62 and another three double triodes (not shown) are connected to earth through a resistor 65 which also forms a common load in the cathode circuits of valves 70, 72 and 66. Valve 70 is normally conducting but is momentarily cut off when the negative pulse on line 11 (see also Fig. 1) occurs at every fourth clock pulse. Each of the double triodes such as 61, 62 is non- conductive only when the stages in registers 2 and 5 which control it are in agreement. If all four stages are in agreement the momentary cutting off of valve 70 by the test pulse on line 11 causes a sharp fall in potential at all the commoned cathodes and the normally non- conducting valve 66 conducts and delivers an output signal via transformer 67.