Which term describes the relationship between the amplitude of the excitation pulse and that of the echo received from the designated target?

The term that describes the relationship between the amplitude of the excitation pulse and that of the echo received from a designated target is sensitivity. Sensitivity in the context of ultrasonic testing refers to the ability of the system to detect echoes from flaws or features within the material. This relationship indicates how well the system can respond to the signals it receives when the excitation pulse is applied.

In this scenario, a higher sensitivity means that the system can detect smaller changes in amplitude of the echo signal relative to the excitation pulse, allowing for better detection of targets or defects. Sensitivity is crucial in non-destructive testing as it affects the overall quality of the inspection and the reliability of the interpretations made from the results.

The other terms, while relevant in different contexts, do not directly define this relationship. Bandwidth refers to the range of frequencies the system operates within, frequency itself relates to the number of cycles per second of a wave, and acoustic impedance affects the transmission of waves through different media but does not describe the amplitude relationship of excitation to echo specifically.