Triaxial cable

Triax provides greater bandwidth and rejection of interference than coax, but is more expensive.

Most of the recently developed broadcast cameras from the leading manufacturers have hybrid single-mode fibre and copper power cores which supersede the older triax connectivity.

The advantages of the hybrid copper/fibre over triax cable are noise immunity due to the optical isolation and extremely high bandwidth.

The core (known as the force) and the inner shield (known as the guard) are kept at approximately the same electrical potential by a voltage buffer/follower, thus the leakage current between them is zero for all practical purposes, despite the imperfections of the insulation.

This technique can provide almost perfect elimination of leakage current but becomes less effective at very high frequencies as the buffer cannot follow the measured voltage accurately.