Patent GB-939223-A (GB)
Title: Improvements in or relating to circuit arrangements for the transmission of coded information
IPC: H04L12/00
Filed: 1961-03-03
Abstract: 939,223. Circuits employing bi-stable magnetic elements. PHILIPS ELECTRICAL INDUSTRIES Ltd. March 3, 1961 [March 7, 1960], No. 7836/61. Class 40 (9). [Also in Groups XIX, XL (b) and XL (c)] A data handling system comprises a number of gating circuits and pulse generators. Each unit is made up from devices, such as that indicated in Fig. 6, which comprise a magnetic core 101 and a transistor 102. A cocking pulse applied to terminal 103 sets the core to state " 1." If subsequently a firing pulse is applied at 104 core 101 begins to flip over to state " 0," and as a result the base of the transistor is driven negative. Current now flows in the feedback winding 108 and a pulse is delivered at terminal 105. Application of a firing pulse to an uncocked unit has no effect. Several firing and/or cocking terminals may be provided, and simultaneous inputs on more than one terminal may be necessary for correct operation. Pulse generator, Fig. 7, is such that a non- recurrent pulse a<SP>1</SP> at 15 produces a pulse train a at 20, while a single pulse a<SP>1</SP> at 16 produces a pulse train #a: the pulse trains a and #a are mutually exclusive. Pulse a<SP>1</SP> at t1 in a repetition cycle cocks unit 10, and a pulse at t3 from a clock pulse generator fires it, giving a pulse at terminal 20 and cocking unit 11. The next pulse, at t2 fires unit 11 whose output, together with the pulse at t2, cocks unit 10 at its coupled cocking terminals. A clock pulse at t3 fires unit 10, and the process repeats, giving a pulse train a at terminal 20. Receipt of a pulse a<SP>1</SP> at t1 fires unit 11. This unit is therefore not cocked when the pulse at t2 arrives so that there is no coincident cocking input to unit 10 and pulse train a ceases. Pulse train a is started. Gating circuit, Fig. 8, provides a pulse train g if trains a and f are present at its input, the train g being stopped immediately on receipt of a pulse e<SP>1</SP>. Unit 22 is cocked by simultaneous pulses a and f at time t3. At t1, a clock pulse fires unit 22, the resulting pulse cocking unit 23 and passing to the output terminal 31. At t5 unit 23 is fired and unit 22 is cocked by its output pulse and the pulse at t5. At t1 the cycle repeats, pulse train g being thereby produced A pulse e<SP>1</SP> at t3 cocks unit 24. This unit is fired by a clock pulse at t4 and in turn fires unit 23. The output of unit 23 alone cannot cock unit 22 so the pulse train g ceases. Further gating circuits, described in detail, also use the basic units described in relation to Fig. 6. Thus in Fig. 9 (not shown) the presence of three pulse trains (in addition to clock pulses) is necessary for a pulse train to be produced, and this train is stopped immediately on receipt of a single pulse at a particular input. Fig. 10 (not shown) gives a gate wherein four pulse trains are necessary, the resultant train being stopped either by a single pulse e<SP>1</SP> or by a fifth pulse train. Fig. 11 (not shown) illustrates a modification of the latter gate in that receipt of the fifth train does not cause immediate cessation of the pulse train at the gate output. A counting circuit is incorporated which causes cessation only after a particular number of pulses of the four pulse trains has been received subsequent to the receipt of the fifth pulse train. Specification 939,222 is referred to.