id	author	title	date	pages	extension	mime	words	sentence	flesch	summary	cache	txt
ap-862	Ritty, A.	Directional Loudspeaker Using a Parametric Array	2006	2	.pdf	application/pdf	1575	82	60	He suggests that the sound pressure of secondary waves (ps) produced by the nonlinear interaction is �p c p t c p t s s p � � � 1 0 2 2 2 0 0 4 2 2 2 � � � � � � , (1) where pp is the sound pressure of primary waves, � is the non- linear coefficient, �0 is air density, and c0 is sound velocity. AP_06_4.vp 1 Headline of a section The nonlinearities of air cause high frequency wave components (primary waves) to interact.	cache/ap-862.pdf	txt/ap-862.txt