spectrographically


spec·tro·graph

S0618300 (spĕk′trə-grăf′)n.1. A spectroscope equipped to photograph or otherwise record spectra.2. See spectrogram.
spec′tro·graph′ic adj.spec′tro·graph′i·cal·ly adv.spec·trog′ra·phy (-trŏg′rə-fē) n.
Thesaurus
Adv.1.spectrographically - by spectrographic means; "the speech spectrum was displayed spectrographically"