Plessey Handel Und Investments A.g.

Douglas Stanley Larner

Velauthar Kopalapillai Thillainayagam

Ronald William Blackmore

Barry Michael Hill

Bipolar digital repeaters are commonly fed with a constant d.c. supply but with the known circuit, the mode of use of transformer-coupled output stage places a limitation on the voltage-amplitude of the output pulses. The 120 M bit/s data transmission system may occasionally require to have its repeaters operate over line-sections of exceptionally high attenuation. The proposed circuit is intended to meet these requirements, using modified connections to the transformer (3 equal windings) and minimal additional components, the maximum peak-output voltage is consequently doubled with no increase in the constant current supply. The new technique, involving a serial connection, ensures that all of the supply current becomes available for the means current in pulses of each polarity separately instead of the two polarities together.

Regenerative repeater circuit arrangement for use in digital data

A circuit for generating synchronization signals from a digital data pulse train having a bit period T and conveying pulses in non-return-to-zero form. The circuit comprising (i) a rectifier device arranged to fullwave rectify the digital data pulse train, (ii) an oscillatory circuit tuned to oscillate with period T and stimulated by the transitions of a waveform produced by the fullwave rectifier device and (iii) a peak detector arranged to produce a bias signal which is proportional to the amplitude of the output of the oscillatory circuit. The bias signal being active upon the fullwave rectifier device to stabilize the amplitude of the waveform produced by the oscillatory circuit.

Circuit for generating synchronization signals

A repeater for a digital data-transmission system using a disparity-displaying digital code comprises a digital regenerator and error-detecting means therefor and in which supervisory control means incorporated in the repeater is operative upon reception of an interrogate pulse signal over one access path also used as a digital-data path, to cause a response signal to be returned over the access path according to the prevailing state of the error detecting means. The response signal comprises a different number of pulses for each of the two possible output states of the error detecting means. The repeater may be the first of a pair of repeaters of a particular repeater station, both repeaters including at least substantially identical digital regenerators and error-detecting means. The repeaters are incorporated in different digital data-transmission paths and are so interconnected that the reception of an interrogate pulse signal by the first repeater is effective in that the aforesaid response signal takes into account th prevailing state of the error-detecting means serving the digital regenerator of the second repeater.

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Maidenhead, United Kingdom

Douglas Stanley Larner