( ( ( An instrument ) ( for ( measuring ( ( the frequency ) ( of ( a ( radio wave ) ) ) ) ) ) ) . )
(ROOT (NP (NP (DT An) (NN instrument)) (PP (IN for) (S (VP (VBG measuring) (NP (NP (DT the) (NN frequency)) (PP (IN of) (NP (DT a) (NN radio) (NN wave))))))) (. .)))
An instrument for measuring the frequency of a radio wave.
(ROOT (S (NP (NNP Am) (NN radio) (NNS waves)) (VP (VBP exist) (PRT (RP in)) (NP (DT the) (ADJP (QP (CD 540) (TO to) (CD 1600))) (NN khz) (NN frequency) (NN range))) (. .)))