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The short answer is, skew will not vary significantly with temperature, because propagation delay will not vary significantly with temperature. Just to clarify, by lane skew, do you mean skew between lanes, or do you mean skew within a lane? Regardless, both forms of skew are normally insignificantly affected by temperature. Delay skew between two conductors within a multiconductor cable is normally primarily due to a mechanical defect, wherein one conductor is simply mechanically longer than the other conductor. However, it is possible to have delay skew between
two conductors having the same length that have dissimilar insulation material, which causes an electrical defect, wherein one conductor is electrically longer than the other conductor.
Propagation delay is a function of the relative permittivity (formerly known as dielectric constant) of the dielectric material used for the wire insulation. The relative permittivity of the wire insulation can be significantly affected
by temperature. However, if both wires of a pair have the same insulation, delay skew is not significantly affected by temperature. In the case of 802.3cy B10GAUTO, in order to meet link segment IL and RL, relatively high quality RF cable must be used, which
will necessarily use relatively high quality and stable dielectric materials. If the same insulation material is used throughout the multiconductor cable(s), any changes due to temperature variation that might affect propagation delay, will have practically the same effect on each wire of a pair of conductors within
the cable, possibly significantly affecting delay, but not significantly affecting skew. NOTE: Delay skew and propagation delay are independent parameters. Delay skew is a differential-mode parameter between any two conductors within a cable. Propagation delay is a common-mode parameter between any two conductors within a cable.
Thus, variation in propagation delay due to variation in temperature is practically independent of variation in delay skew. Dave Hess, Cord Data To unsubscribe from the STDS-802-3-B10GAUTO list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=STDS-802-3-B10GAUTO&A=1 |