GB1489768A - Method for reducing the electrical couplings in telecommunications cables - Google Patents

Abstract

1489768 Reducing coupling in telecommunication cables SIEMENS AG 5 Nov 1974 [5 Nov 1973] 47811/74 Heading H1A To reduce electrical coupling in telecommunication cables comprising at least two conductor cores 9 stranded together, conductors 8 are stranded together with a direction of twist which is reversed at successive points along the cable, the lay length varying in each section of constant twist direction and the spacing between said successive points being varied in steps between two values and on reaching one value is restored in one larger step to the other value the said larger step being equal to at least half the maximum value of Sn.Sm/Sn + Sm where Sn and Sm are any two values of lay length. This formula is said to represent the period of a sine or cosine curve representing the distribution of coupling along the cable. The apparatus of Fig. 4 comprises storage devices 5 and 18 rotating at different speeds and having storage capacities oppositely variable by reciprocating movement of plate 12 carrying rollers 4 and 19. The direction of twist is reversed when the direction of movement of frame 12 reverses. A length pulse emitter emits a voltage pulse per unit length of core 9 produced and a counter starts counting the pulses after the frame has moved a basic distance from the centre position corresponding to the production of a length ¢To of core. The counter reverses the movement of the frame after a number of pulses which increases by one on each successive movement, i.e. after 0, 1, 2, 3 up to a pulses thus steadily increasing the distance moved between reversals of twist.