Which term means that the output signal is just like the input signal in all respects except amplitude?

The term that indicates the output signal is identical to the input signal in every aspect except for amplitude is fidelity. Fidelity refers to the degree with which an audio, video, or other signal reproduces the characteristics of the original signal. High fidelity systems aim to reproduce the input signal as accurately as possible, maintaining the integrity of its waveform, frequency, and timing, with the only variable being the amplitude.

In contrast, clarity, accuracy, and precision describe different aspects of signal representation and measurement. Clarity often pertains to how well defined or distinct a signal is, while accuracy relates to how close a measured value is to the true value. Precision involves the repeatability of measurements but does not necessarily imply that those measurements are close to the true value.