An amplifier takes in an input signal and outputs the signal at a greater amplitude. A nonlinear amplifier will not faithfully reproduce the signal and adds distortion to the waveform, which degrades system performance. Testing the linearity of an amplifier, therefore, is critical to maintain high-fidelity communications.
This post explores the concepts of amplifier linearity and efficiency as well as reviews amplifier linearity measurement methods.
Amplifier Linearity & Efficiency
If an amplifier behaves linearly, then the output signal will change proportionally to the input signal, meaning the ratio between the two will be consistent (i.e., a specified gain).