To understand a system with an input and an output, such as an audio amplifier, we start with an ideal system where the
When … See more

THD+N means total harmonic distortion plus noise. This measurement is much more common and more comparable between devices. It is usually measured by inputting a sine wave, notch filtering the output, an… See more

The distortion of a waveform relative to a pure sinewave can be measured either by using a THD analyzer to analyse the output wave into its constituent harmonics and noting the amplitude of each relative to the fundament… See more

For many standard signals, the above criterion may be calculated analytically in a closed form. For example, a pure square wave has THDF equal to
The sawtooth signal possesses
The pure s… See more