Paired electrical cable having improved transmission properties and

Abstract

A pre-twisted cable pair and a method for processing such pairs into an electrical cable having improved electrical and mechanical properties is disclosed. At least one insulated wire for transmitting electrical signals is pre-twisted prior to pairing with another insulated wire. As the pre-twisted wires are paired by a conventional double-twist machine which imparts back-twist, the detrimental electrical effects caused by irregularities in the individual wires are cycled over a very short distance, resulting in a cable pair having lower structural return loss, near-end crosstalk, and insertion loss than wires paired without any pre-twist. These pre-twisted wires may be united into a jacketed electrical cable by a continuous-extrusion jacketing process in which an optimal dielectric constant is maintained around each individual cable pair. This is made possible due to a unique die and tip configuration which provides ridges to space the pairs apart and provide optimum air dielectric, but prevents jacketing compound on the interior of the resulting electrical cable jacket from joining to isolate each individual cable pair during the extrusion process. The resultant electrical cable has superior electrical and mechanical properties when compared to similar electrical cables fabricated by conventional techniques.