For emerging serial copper applications such as NGIO, dual speed Fibre Channel,
and Gigabit Ethernet, traditional quad cables are found to be lacking in crosstalk
and EMI performance at multi-gigabit transfer rates. Since pairs in quad constructions
are not individually shielded, a significant impedance discontinuity and source of
crosstalk occurs at the connector where pairs are separated for termination.
Spectra-Strip has addressed this problem with its SKEWCLEARÒ
line of dual shielded serial cables. The cable line consists of 2, individually
shielded 150 ohm parallel pairs, extruded with foam polyolefin dielectric. Pairs
are available from 30 awg through 22 awg for both internal and external applications.
Key advantages of the SKEWCLEAR construction are extremely low TD and amplitude skew,
and superior crosstalk performance in bidirectional applications. In addition, the
grounding of pair shields to the overall frame ground cable shields throughout the cable
length yields better EMI performance than quad type cables. Crosstalk at the connector
is minimized due to the heat sealed pair shields, which can be brought very close to the contacts.