Patent GB-911547-A (GB)
Title: Improvements in or relating to regenerative telegraph repeaters
IPC: H04L25/04
Filed: 1959-04-13
Abstract: 911,547. Code telegraphy. PHILIPS ELECTRICAL INDUSTRIES Ltd. April 13, 1959 [April 16, 1958], No. 12438/59. Class 40 (3). A regenerative repeater which can handle telegraph signals from a number of incoming lines comprises a series of magnetic memory cores associated with each line, each series being coupled to a set of common memory cores, and a pulse distributer which switches between the several series and the common cores. The condition of each incoming line is tested at a time corresponding to the approximate centre of each code element of an undistorted signal. The telegraph signals over the several lines are not in step and hence the start elements begin at random. Start elements are distinguishable from false start signals. In Fig. 1, TA, TB ... denote incoming lines and KA1-KA9, KB1-KB9 ... the series of cores associated with them. Pulses from a generator PG1 are distributed cyclically by distributer PV1 to the cores KA1-KA8, KB1- KB8 ... a reading and a recording pulse being sent in turn to each series. Considering line TA, when the line is in the rest condition gate PA is open and core KA1 is in state "1." A reading pulse causes core KA1 to pass a pulse via amplifier L1 to the common core K1 which assumes state "I." A pulse also passes through gate PA to gate P, open due to the pulse from core KA1, which gives an output pulse to the cores K2- K8 and places these in the states " 0," " 0," "1," "1," "1" "1" and "1," Fig. 2, line a, no matter what states cores KA2-KA8 are in. This will be referred to as the initial states. The next pulse from distributer PV1, a recording pulse, causes cores KA1-KA8 to assume the states held immediately before by cores K1- K8. Each line at rest is treated in this way, and on the next reading pulse to cores KA1-KA8 the cycle repeats, line b, Fig. 2. When line TA is in the working condition, e.g. on reception of a start signal, gate PA is shut, and therefore no pulse can be passed through gates PA and P to set cores K1-K8 to their initial states. A reading pulse sets cores K1-K8 to the states in line 1 of Fig. 2-amplifiers L5 and L8 set K2 and K6, respectively, to state " 1 " only if their two respective inputs are different. On the subsequent recording pulse cores KA1-KA8 assume the states of cores K1-K8. This process continues, Fig. 2, until line TA again comes to the rest condition. On the eighth reading pulse cores K2-K5 are all in state " 1 " and so a coincidence gate CS1 emits a pulse which, if the line TA is in the working condition, sets K9 to state "1," and also, via amplifier L1, sets K1 to state " 0." On the next recording pulse KA9 is set to the state of K9, which state is indicative of the condition of the line TA. Should the start signal be a false signal, i.e. if it ends before the eighth reading pulse, gate PA will open again, cores K1-K8 will revert to their initial states and core KA9 will not be changed to state "1." Cores K6-K8 are all in state " 1," at each seventh read pulse, but coincidence gate CS2 gives an output pulse only when there is also an input from gate CS1. This happens on the ninety-eighth pulse only, corresponding to the centre of the stop signal, when the pulse passes via conductor G6 and amplifier L1 to place core K1 in state "1" and via gate P to place cores K2-K8 in their initial states ready for the next start signal. The cores KA9, KB9 . . . are thus in states indicative of the conditions of lines TA, TB . . . and these states are read out by the telegraph reception distributer of Fig. 4 for feeding a reperforator or other recorder. To send regenerated signals to a further set of lines instead of to a printer, cores K9, KA9, KB9 . . . and amplifier S9 are omitted, and the circuitry shown in broken line is added. In this ease the pulse from coincidence gate CS1 is passed to a gate PAU together with a reading pulse. The gate is also connected to the line TA. Gate PAU controls a trigger circuit TU which is then set to a condition corresponding to that of the line and which feeds the regenerated signal to line UA. At the reception distributer, Fig. 4, pulse generator PG2 feeds distributer PV2, a reading and a recording pulse being passed to each series of cores KA10-KA14, KB10-KB14 ... and a recording pulse being passed to cores KA15-KA19, KB15-KB19 . . . and cores K10-K19, in sequence every pulse element period. On the first read pulse core K10 assumes the state of KA9, " 1 " in the case of a start signal, and on the recording pulse this state is set on KA10. On the fifth recording pulse core KA14 is in the state corresponding to the start signal and KA9-KA13 are in states corresponding to the five code elements. At the sixth reading pulse, a pulse from KA14 passes via an amplifier L14 and a slight delay (not shown) to cores K10-K14, which by now are in the states that had been held by cores KA9-KA13, and to cores K15-K19, which assume the states of K10-K14. The next recording pulse places KA15-KA19 in states previously held by K15-K19, i.e., in states corresponding to the five code elements; this information may be read out simultaneously from the cores by means not described. Specification 911,548 is referred to.