What is a metallic time domain reflectometer (MTDR) used for?

A metallic time domain reflectometer (MTDR) is primarily utilized for evaluating the electrical characteristics of cables by measuring reflected voltage at specific moments in time. This ability allows technicians to detect issues such as faults, breaks, or impedance mismatches in a cable without the need for physical access to the entire length of the cable.

When a signal is transmitted through a cable, any discontinuity or fault in the cable will reflect a portion of that signal back toward the source. The MTDR captures these reflected signals and analyzes them to display information about the distance to the fault and the nature of the fault itself. This makes it a valuable tool in ensuring the integrity of cabling systems, as well as in maintenance and troubleshooting processes.

The other options pertain to functions that do not align with the primary use of an MTDR. For instance, amplifying electrical signals or maintaining temperature in coaxial cables involves entirely different equipment and techniques not associated with the reflective measurement capabilities of an MTDR.