For what purposes can a TDR be used, considering its sensitivity to impedance variations?

Answer: B — Verify cable impedance characteristics

A Time Domain Reflectometer (TDR) is an invaluable tool primarily used for identifying and verifying cable impedance characteristics. It sends electrical pulses down a cable and measures the reflections that occur when the signal encounters different types of impedance discontinuities in the line. These reflections can provide detailed information about the physical parameters of the cable, including its length, the location of faults, and any issues related to impedance mismatch. Understanding cable impedance is critical in various applications, particularly in telecommunications and traffic signal systems, where maintaining signal integrity is essential for system reliability. By analyzing the reflected signals, technicians can ascertain whether a cable meets the required specifications and diagnose any potential issues that could affect performance. The focus of a TDR on impedance makes it unsuitable for purposes such as measuring temperature variations, tracking data transmission speeds, or monitoring general environmental conditions. These tasks rely on different technologies and measurement principles that are outside the scope of what a TDR is designed to do. Therefore, its primary use is as a tool for verifying cable impedance characteristics.