Harmonic distortion

This type of measurement is used to determine harmonic distortions employing sine signals for excitation.

The plot shows the distortion spectrum of an overdriven input of a Robo3 measurement system with an excitation frequency of 1.3kHz and the harmonic components at multiples of this frequency (as well as some minor intermodulation components).

The parameters for the measurement are to be set in the Measurement setup. As an additional parameter the frequency of the sinusoid excitation signal can be specified in Frequency [Hz]. The frequency entered here is adjusted automatically, so that with the FFT length selected the resulting number of signal periods is an integer, and hence the signal ends on a zero crossing.

Level settings are made in the Exciter setup, the configuration of the amplifiers to be used is done in the Amplifier setup.

Using Normalisation the measurement can be referenced to different reference values: to a voltage of 1V, to the level of the excitation signal (excitation level), or the measured signal is displayed absolutely (nothing).

In Processing the post-processing of the measuring results is to be configured.

If the option Show distortion is active, after the measurement the analysis by the Distortion Info window is launched automatically. The excitation frequency used for measuring is automatically transferred to the analysis window.

Cancel aborts the measurement, OK starts the process.