Patent GB-748730-A (GB)
Title: Improvements in or relating to electrical signal-translating equipment
Inventor: WRIGHT ESMOND PHILIP GOODWIN
IPC: H03M5/00
Filed: 1953-11-04
Abstract: 748,730. Telegraph transmitters. STANDARD TELEPHONES & CABLES, Ltd. Nov. 4, 1953, No. 30509/53. Class 40 (3). An arrangement for transmitting signals in a start-stop printing-telegraph code comprises a number of storage devices in each of which is recorded the combination representing one of the signals in said code and means responsive to reception of a signal to be transmitted to extract from the appropriate storage device the code combination corresponding to said signal. In the arrangement described, the signals are recorded on a drum having consecutive sections of a track CT with control elements between the successive recordings. The drum has separate tracks T1, T2, T3 providing a clock 1 train of pulses at the beginning of each element, a clock 3 train at the centre of the fifth element of each recorded signal and a clock 2 series occurring at the mid point of the control element and produced by imposing at network SE a time delay of the element period on the clock 3 train. A clock 4 train of sampling pulses occurring at the mid points of the recorded elements is derived by feeding the clock 1 pulses through a circuit HE producing a delay equal to half the element period and a gating circuit G1 inhibited by the clock 2 pulses. The third track T3 produces synchronizing pulses ZP at the centre of the control element at the beginning of the track. The ZP pulses bring the distributer 31C to its initial position and the clock 3 pulses step the distributer until an output from 31C1-31C32 coincides with an output from C1-C32 corresponding to the signal to be transmitted, and which may be selected by a keyboard, and opens one of the gates G2 ... G33. When gate G34 opens on the next clock 2 pulse, 31F operates to 31F1 so that G35 opens on the clock 1 pulses and produces five stepping pulses DSP. Additionally, G36 opens to pass the clock 4 train to provide examining pulses EP. The pulses DSP open gate G37 to the marking pulses from the track CT which are recorded on segment 1 of the register 31R which is stepped by the examining pulses EP until the code combination is stored on 31R6 ... 31R2. With 32F operated to 32F1, the next clock 2 pulse opens gate G39 to operate 33F to 33FO and the next PS pulse from a source providing pulses at a desired signal transmitting frequency steps 32C from 32C8 to 32C1. The following PS pulse opens gate G42 so that the TR 34F is energized to 34FO to operate relay 1 to actuate its contact tr1 to send a space element to the line. Subsequent pulses step the register 32C from positions 32C2 ... 32C6, and pulses PSB, delayed relative to the pulses PS, in combination with pulses from 32C step the pattern along the register 31R. If the element on 31R6 is a space, 31R6-0 is positive and a mark on 31R6 makes 31R6.1 positive. Gates G43, G44 respectively are opened in response to spaces and marks and consequently control gate G42 or G45 to operate the relay TR/1 to the spacing or marking position. A pulse PSB in conjunction with a pulse from 32C7 returns 31R to the position 31R1, and the pulses 32C7, 32C8 in conjunction with the PS pulses operate 34F to 34F1 to cause relay TR/1 to send a mark for two periods to constitute the stop element. The impulse from 32C8 restores 33FO to 33F1. A circuit 35F, with 35FO normally operated, is provided to ensure that each signal to be translated can cause solely one translation. When a signal is to be translated a pulse appears on Q at the same time as that on one of the outputs C1 ... C32 and the next clock 2 pulse opens gate G47 to operate 35F to 35F1 thus removing the inhibiting control from the gate G34 so that 31F can be operated and the next clock 2 pulse, after five DSP and EP pulses have been produced, operates 32F to 32FO and through gate G48 restores 35F to 35FO so that the gate G34 is inhibited. In a modified arrangement, Figs. 4 to 6 (not shown), the storage track employs 32 elements with marks and spaces so arranged that with the rotation of the track from a normal position by a number of steps corresponding to a particular signal to be transmitted the next five elements on the track in relation to the fixed position provide the code combination corresponding to the signal. The circuit arrangement for this modification is described in connection with Fig. 6 (not shown).