| 摘要 |
<p>1437531 Communication systems SOC ITALIANA TELECOMUNICAZIONI SIEMENS SpA 15 June 1973 [15 June 1972] 28647/73 Heading H4R [Also in Division H1] For the avoidance of crosstalk in a timedivision communication system, a cable has inner and outer conductors each comprising at least one set of twisted mutually-insulated wires, each wire having a diameter of order of magnitude #, i.e. the skin-effect penetration depth at the sampling frequency, the inner conductor being disposed generally along the axis of the cable; and a dielectric of strongly non-polar material. The cable is coaxial, having an inner conductor CI comprising at least one set of twisted mutually-insulated wires, e.g. Litz wire, so disposed that each strand successively occupies every radial position in the conductor. The dielectric IA is of polythene or PTFE. The outer conductor CW is a plurality of Litz wires laid helically around the dielectric. For transmitting signals at a sampling frequency of 0À6 MHz the inner conductor CI may comprise 180 strands, and the outer conductor 132 strands, each of 0À04 mm, diameter and a twisting pitch of 12 mm. The cable may be arranged as a speech path in the form of a loop (Fig. 6, not shown) on the "ring-main" principle, having branches for connecting other circuits.</p> |
