A term that defines any change in a sinusoidal signal when the output is not a linear reproduction of the input is:

The correct term that defines any change in a sinusoidal signal when the output is not a linear reproduction of the input is distortion. Distortion occurs when the output waveform significantly deviates from the expected shape based on the input, resulting in alterations that may affect amplitude, frequency, or phase characteristics. This can lead to the introduction of harmonics or unwanted frequency components not present in the original signal, impacting the fidelity and accuracy of the signal being analyzed. As such, understanding distortion is crucial for ensuring the integrity of measurements in Eddy Current Testing and other applications where waveform accuracy is vital.

The other terms, while related to signal characteristics, do not describe the phenomenon of non-linear reproduction. Linearity pertains to the relationship between input and output being proportional, phase shifting refers to a change in the timing of the wave, and dynamic range involves the difference between the smallest and largest signal levels in a system. None of these capture the essence of how an output alters in a non-linear way compared to its input.