( ( The ( Fourier Transform ) ) ( ( ( ( ( changes ( an ( amplitude-vs-time graph ) ) ) ( into ( an ( amplitude-vs-frequency graph ) ) ) ) , ) ( showing ( which ( ( ( sines or ) cosines ) ( could ( be ( used ( to ( construct ( the signal ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NNP Fourier) (NNP Transform)) (VP (VBZ changes) (NP (DT an) (JJ amplitude-vs-time) (NN graph)) (PP (IN into) (NP (DT an) (JJ amplitude-vs-frequency) (NN graph))) (, ,) (S (VP (VBG showing) (SBAR (WHNP (WDT which)) (S (NP (NNS sines) (CC or) (NNS cosines)) (VP (MD could) (VP (VB be) (VP (VBN used) (S (VP (TO to) (VP (VB construct) (NP (DT the) (NN signal))))))))))))) (. .)))
The Fourier Transform changes an amplitude-vs-time graph into an amplitude-vs-frequency graph, showing which sines or cosines could be used to construct the signal.
(ROOT (S (NP (NNP Line) (NNS graphs)) (VP (VBP are) (ADJP (RB especially) (JJ useful) (PP (IN for) (S (VP (VBG showing) (NP (NNS changes)) (PP (IN over) (NP (NN time)))))))) (. .)))