Which parameter is most directly related to impedance mismatch in a cable system?

• A. Insertion Loss
• B. Crosstalk
• C. Return Loss
• D. Propagation Delay

Answer: (C)

Impedance mismatch causes signals to reflect back toward the source, and return loss is the measure that directly quantifies how much of that energy is reflected. In other words, it tells you how well the line is being terminated and how much of the forward signal shows up as a backward wave. A higher return loss value (in dB) indicates less reflected power and thus better impedance matching, which is exactly what you want in a well-designed cable system.

Insertion loss, by contrast, is about the overall loss along the path of the forward signal—how much strength is reduced as it travels. Crosstalk measures unwanted coupling between adjacent conductors, not reflections due to impedance. Propagation delay is about how long the signal takes to travel from one end to the other, not about how much energy reflects back.