Intra-pair Skew Impact Analysis of High-speed Cables for HDMI Interface

Abstract

In this paper, the coaxial and shielded-twisted pair (STP) cables with intra-pair skew was analyzed by frequency domain analysis method by the equations in close-to-real intra-pair skew setup for high definition multimedia interface (HDMI) interface. For the high-speed interface, the intra-pair skew has become critical factor in terms of signal integrity. Heretofore, the intra-pair skew has not been commonly investigated in frequency domain for the high-speed data rate. To verify the intra-pair skew impact on the high-speed interface, the intra-pair skew location was distributed in the coaxial and STP cable assemblies for the real cable setup. Next, the skew impact was verified using frequency domain analysis and the eye-diagram. As the result, by the frequency-domain analysis, the differential loss and the mode conversion of coaxial cable assembly deteriorated due to the intra-pair skew, but STP did not deteriorate. Furthermore, the eye-diagram of the coaxial cable assembly with skew had smaller opening than without any skew, but of STP had little change.