Acoustics 08 Paris Parametric audible sounds by phase-cancellation excitation of primary waves T. Kamakura, S. Sakai, H. Nomura and M. Akiyama Dept. of Electronic Eng., Univ. of Electro-Communications, 1-5-1, Chofugaoka, 182-8585 Chofu-shi, Japan [email protected] 4367 Acoustics 08 Paris !" # $%& ' ( ) * ** + ,$ * -'$ * ,& .,-,/ ( *$%& ' ' ** ' 0" $ ' ' 1 ( ' ' + ' ' ) ' 02* 3 * ' ( ' ' * ' *$ * ( * * %* (* ' ' * * ( $' *' ' ' ' * 1 ' ' 4$ & 5*,( ( ' 6 & 708 % * ' * % * ' * ' ' * 5 9 , * * & 78 :* * * ' * 1 ' )$* 4368 7!8 '* * '* ' ' * ' ( ) * ** ,$ * -'$ * ,& .,-,/ * ( ( ' 9 ' ( ' 1 '* 02* 5 0 ' ( ' ' ½ ¾ .½ ¾ / ½ ; ½ .½ < / . / .0/ ¾ ; ¾ .¾ < / ½ ; ½ ¾ ; ¾ * 5 ½ ¾ ½ ¾ ' 5 * ; 1 3 * = ' 5 ' ,-, Sound pressure level [dB] Acoustics 08 Paris 40 2 kHz : out−of−phase : in−phase 4 kHz 6 kHz 10 5 G ' 0> ' & #*$%& ; 0" ' ( * ' ' ' 7>8 ¿ 80 1 Axial distance [m] 5 0 ¾ 38 kHz 120 Æ 0 4 ** * * ' * 5 0* ' # 5 & ( 1 '* ( * *$%& 0 1 0 ' ** ' * ' ' 5 0 ( ' * ' # $%& H $%& ' ! ' # 5 ! * ' F' 0* ¾ ¾ ; ¼ ¾ < Æ¿ ¿ < ¿ ¾ ./ ¼ ¼ ¼ ¼ ¼ Æ ( ' * Æ ? ¾ ; ¾ ¾ < ¾ ¾ @ ' . / ; ¼ @ ' ( * ' ' & 1 ' 3 ; A* B A**B * $ ,-, ' ( ' ' * 5 ' ½ ; !" $%& ¾ ; # $%& ; 0 ' CC D ; 4 ; >E ' Æ 7#8 F* * ( 5 ' ' 0> ' ( ' * ** * * 120 Sound pressure level [dB] 38 kHz Æ 80 2 kHz 40 −100 : out−of−phase : in−phase 4 kHz 0 Radial distance [cm] 100 5 ! # ' #*$%& ; 0" Æ 4369 Sound pressure level [dB] Acoustics 08 Paris 120 38 kHz 100 Solid: 4 m Dots: 2 m 80 2 kHz 60 0 180 Phase difference [deg.] 5 > 4 9 C0 ' & 0 # $%& 5 # * !"*$%& *$%& # ' 1 ' ' ' 5 ( ' 0 * ** ' ' * >* ' ' 1 * + ( ' 2 C 5 # 9G@ # !"*$%& * $%& ( 1 ( * $ +' ( * 0" ' ' ¼ ; 0> ' 00 # @$ 000 ' ' 3 * * . 5 H/ ' ' ' # 0" IÔÔ 020 IÔÔ 1 ! 4 > E 5 H * !" $%& # $%& *' '* ' 0" 3 ' A9B * ' !" $%& # $%& 5 C./ 9' ' ' ,-, F* ' 0> ½ ; ¾ ; > G .0/ ' ' ' ' ' 3 * 0 ' * ' * '* 0 Æ Æ Æ Æ Æ ) 02 5 > C0 & 0 ) ' #*$%& > $%& ' 0 ' # $%& * * ' ' ' * 0C 0C 3 ' 3 5 H ) 4370 Acoustics 08 Paris 80 38 kHz 40 kHz Sound pressure level [dB] Sound pressure level [dB] 140 In−phase 120 Out−of−phase 100 (a) 1 Propagation distance [m] 10 2 kHz Out−of−phase In−phase 60 4 kHz 40 0.1 (a) 1 Propagation distance [m] 10 120 38 kHz 40 kHz Receiving point : 4 m Sound pressure level [dB] Sound pressure level [dB] In−phase Out−of−phase 100 80 Receiving point : 4 m −100 (b) 0 100 40 (b) 5 C F* !" $%& # $%& ./ ' # .'/ 9' ' ,-, F* ' 0> ' Out−of−phase In−phase 4 kHz 20 −100 Radial distance [cm] 2 kHz 60 0 100 Radial distance [cm] 5 " F* ( $%& # $%& ./ ' # .'/ 9' ' ,-, J *$%& # ' ( ' 5 C.'/ @$ ' :' ( * '' ' & Æ * 1 ' * ' ( ' B 1 ( $ ' 7H8 ** ' ' 0 > 4 5 " * ' ' ' = 0C ' 0 $%& 5 *$%& ( G ( ' $ ' * ** * ' ' > ' * $ ' ' > 1 5 ".'/ * *$%& ' 1 ' * ( * .#*$%& / $ +* ' 6 ' ' 1 * * ' % 4371 Acoustics 08 Paris ' ' 2 ' $ * '* 55 & ; H 0!> 5 C./ ? ' #> > ./ ' > ' 1 ' ' = 55 * 3 * * * 1 ' ( ' * ' ' 0" G $ ' K* * 9 D./ 02!00> L 9 G 9 Æ 708 D 4 4$ M? '* N :* ? O !>!*!H! .022>/ 78 9 9 , M? 'N L L G !!0*!!H .#/ 7!8 , ? ,$ ? ?& M@* )$ * N L L G ###"*##> .H/ 7#8 % ) @ 4 9 L -$ J $$ J ? % M ' 5 NL 9 H"*H"!.022>/ 7>8 ? 5 % 4 @ ?M ? * N ' ? 5 % J $$ . G 9 J 022C/ 4 ! 7H8 % , , $ ,$ M )* ' N D 1)14) .0222/ 4372
© Copyright 2026 Paperzz