EPD cable

Shielding of cable is important in many applications. Shielding helps to minimize crosstalk within the cable, prevents intervention from external interference, or eliminate radiation from the cable itself. The design of cables to provide effective shielding over a broad frequency spectrum is complex, and cables must be tailored to specific electromagnetic environments. Choices range from simple aluminized polyester film that provides electrostatic shielding to progressively more complex shielding with plated copper braids and Mu metal wraps. Performance of conventional braiding can be significantly improved by computer optimization. This tightly controlled process can significantly increase shielding performance of a basic braided shield with minimal weight penalty or increase in optical coverage. Supershielded cables combine Mu metal wraps with optimized braids to provide even further enhanced performance, especially at low frequencies.

To assess the effectiveness of a shield, TE has adopted the line injection method as described in IEC 1196-1 to measure the surface transfer impedance (Zt) of a cable shield. To determine the surface transfer impedance across a range of frequencies, a drive signal is generated by the internal tracking generator of a spectrum analyzer. The voltage is induced on the center conductor of the sample which is amplified and returned to the signal generator for measurement.