a coaxial cable consist of an inner conductor and an outer conductor separated by insulating material, so does the inner conductor connect to a positive terminal and the outer conductor connect to a negative terminal, or the inner conductor connect to a negative terminal and the outer conductor connect to a positive terminal?
just making sure i understand the response, but the inner conductor transmits the signal and the outer conductor is connected to ground? you said outer shield, and that is the outer conductor?
The forward signal current is carried by the inner conductor and the return signal current by the outer conductor, but the outer conductor us typically maintained at ground potential at both ends of the cable.
It's similar to having two separate wires with one carrying the signal and the other being the ground (return) wire between the two ends.
All signals always require a return connection, of course.