Normalised spectrum and pseudo-continuum predicted by SUPPNet (active) with default sampling and smoothing parameters. As flux is already normalised, pseudo-continuum should equal 1 in the whole domain. The upper panel shows the influence of noise and resolution on normalisation results. The results are generally consistent with the exception of noisy, SNR = 30, medium resolution, R = 10⁴, spectra (see the green lines). In such a case the pseudo-continuum is placed too high. It is worth mentioning that such low resolution is outside of the training data domain where the resolution is not lower than 4 × 10⁴. This limitation can be overcome by increasing a sampling step or by extending the training set to include lower resolution spectra. The lower panel shows the influence of the projected rotational velocity on the normalisation result. The predictions are generally consistent and differ by less than 0.01.