| 摘要 |
<p>The cable comprises individual conductor sets (18) having, typically, between 2 and 8 twisted pairs of insulated conductors occupying a notionally cylindrical space (30). Optionally, 4 or more twisted conductors comprise a set. Each set is itself sheathed. The notional cylinders are tangentially located w.r.t. the inside surface of an overall sheath (34), thus maximising the separation (32) between adjacent sets. A screen (36) separates the sheath from the central plastic foam filling, e.g. a low density polyethylene. The filling is centrally injected and has low high frequency losses and which does not adhere to the direct conductor insulation. The filling also contains dissolved or compressed gas that expands after injection. Rotation during construction produces sets of twisted conductors which follow helical paths within the sheath.</p> |
