(12) United States Patent
`(12) United States Patent
`Marash et ai.
`Marash et al.
`
`111111
`
`1111111111111111111111111111111111111111111111111111111111111
`US006363345Bl
`US006363345B1
`US 6,363,345 BI
`(10) Patent No.:
`US 6,363,345 B1
`(10) Patent No.:
`(45) Date of Patent:
`Mar. 26,2002
`(45) Date of Patent:
`Mar. 26, 2002
`
`(54) SYSTEM, METHOD AND APPARATUS FOR
`(54) SYSTEM, METHOD AND APPARATUS FOR
`CANCELLING NOISE
`CANCELLING NOISE
`_
`_
`_
`Inventors: Joseph Marash, Haifa; Baruch
`(75)
`(75) Inventors. ,lIgostgm Mar'a'sh, Haiféa), lilarpch
`Berdugo, Kiriat-Ata, both of (IL)
`er ugo’ Klnat'Ata’ 0t 0 (IL)
`(73) Assignee: Andrea Electronics Corporation,
`(73) Assignee: Andrea Electronics Corporation,
`Melville, NY (Us)
`Melville, NY (US)
`
`( *) Notice:
`( * ) Notice:
`
`Subject to any disclaimer, the term of this
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 0 days.
`U.S.c. 154(b) by 0 days.
`
`(21) Appl. No.: 09/252,874
`(21) Appl- N04 09/252,874
`(22) Filed,
`Feb 18’ 1999
`Feb. 18, 1999
`(22) Filed:
`
`Int. CI? ................................................ G10L 21/02
`(51)
`(51) Int. Cl.7 .............................................. .. G10L 21/02
`
`_
`_
`U.S. CI. ........................ 704/226; 704/233; 704/205
`(52)
`(52) US. Cl. ...................... .. 704/226, 704/233, 704/205
`.
`Field of Search ................................. 704/270, 500,
`(58)
`(58) Fleld 0f Search ............................... .. 704/270, 500,
`704/233, 200, 201, 205, 226, 227, 228,
`704/233> 200> 201> 205> 226> 227> 228>
`211, 216; 379/22.08, 392.Q1, 3, 406.01,
`211> 216; 379/22~08> 392~01> 3> 406~01>
`406.12,406.13,406.14,406.05
`406~12> 406~13> 406~14> 40605
`_
`References Cited
`References Clted
`U_S_ PATENT DOCUMENTS
`U.S. PATENT DOCUMENTS
`
`(56)
`(56)
`
`2,379,514 A
`2,379,514 A
`2,972,018 A
`2,972,018 A
`3,098,121 A
`3,098,121 A
`3 101 744 A
`3,101,744 A
`’
`’
`
`7/1945 Fisher
`7/1945 Fisher
`2/1961 Hawley et al.
`2/1961 Hawley et 211.
`7/1963 Wadsworth
`7/1963 Wadsworth
`8/1963 Wamaka
`8/1963 Warnaka
`
`(List continued on next page.)
`(LiSt Continued 0H IleXt page.)
`FOREIGN PATENT DOCUMENTS
`FOREIGN PATENT DOCUMENTS
`
`DE
`DE
`DE
`DE
`DE
`DE
`EP
`5;
`EP
`EP
`EP
`EP
`EP
`EP
`EP
`EP
`EP
`
`3/1978
`2640324
`3/1978
`2640324
`3/1988
`3719963
`3/1988
`3719963
`9/1991
`4008595
`9/1991
`4008595
`9/1982
`0059745 B1
`Z;
`0380290 A2
`8/1990
`10/1990
`0 390 386
`0390386
`10/1990
`2/1991
`0 411 360 B1
`0411 360 B1
`2/1991
`0 509 742 A2 10/1992
`0509742 A2
`10/1992
`0 483 845
`1/1993
`0483845
`1/1993
`
`OTHER PUBLICATIONS
`OTHER PUBLICATIONS
`B.D. Van Veen and KM. Buckley, “Beamforming: A Ver
`B.D. Van Veen and K.M. Buckley, "Beamforming: A Ver(cid:173)
`satile Approach to Spatial Filtering," IEEE ASSN Magazine,
`satile Approach to Spatial Filtering,” IEEE ASSN Magazine,
`V01‘ 5, NO‘ 2, Apr‘ 1988, pp‘ 4_24~
`vol. 5, No.2, Apr. 1988, pp. 4-24.
`Beranek, Acoustics (American Institute of Physics, 1986)
`Beranek, Acoustics (American Institute of Physics, 1986)
`pp. 116-135.
`pp. 116—135.
`Boll, IEEE Trans. on Acous., vol. ASSP-27, No.2, Apr.
`Boll, IEEE Trans. on Acous., vol. ASSP—27, No. 2, Apr.
`1979, pp. 113-120.
`1979, pp. 113—120.
`Daniel Sweeney, “Sound Conditioning Through DSP”, The
`Daniel Sweeney, "Sound Conditioning Through DSP", The
`_
`_
`Equipment Authority, 1994.
`Equipment Authority, 1994.
`(List continued on next page.)
`(List continued on next page.)
`Primary Examiner—Richemond Dorvil
`Primary Examiner-Richemond Dorvil
`(74) Attorney, Agent, or Firm—Frommer LaWrence &
`(74) Attorney, Agent, or Firm-Frommer Lawrence &
`Haug; Thomas 1. Kowalski
`Haug; Thomas J. KoWalski
`(57)
`ABSTRACT
`ABSTRACT
`(57)
`
`A threshold detector precisely detects the positions of the
`A threshold detector precisely detects the positions of the
`noise elements, even within continuous speech segments, by
`noise elements, even Within continuous speech segments, by
`determinin Whether fre uenc S ecmlm elements, or bins,
`determining whether frequency spectrum elements, or bins,
`g
`9
`Y P
`of the input Signal are Within a threshold Set according to
`of the input signal are within a threshold set according to
`current and future minimum values of the frequency spec
`current and future minimum values of the frequency spec(cid:173)
`trum elements. In addition, the threshold is continuously set
`trum elements. In addition, the threshold is continuously set
`and initiated Within a predetermined period of time. The
`and initiated within a predetermined period of time. The
`estimate magnitude of the input audio signal is obtained
`estimate magnitude of the input audio signal is obtained
`using a multiplying combination of the real and imaginary
`using a multiplying combination of the real and imaginary
`part of the input in accordance with the higher and lower
`part of the input in accordance With the higher and loWer
`values betWeen the real and imaginary part of the signal. In
`values between the real and imaginary part of the signal. In
`order to further reduce instability of the spectral estimation,
`order to further reduce instability of the spectral estimation,
`a tWo-dimensional smoothing is applied to the signal esti
`a two-dimensional smoothing is applied to the signal esti(cid:173)
`mate using neighboring frequency bins and an exponential
`mate using neighboring frequency bins and an exponential
`average over time. A filter multiplication effects the subtrac(cid:173)
`average over time. A?lter multiplication effects the subtrac
`tion thereby avoiding phase calculation dif?culties and
`tion thereby avoiding phase calculation difficulties and
`effecting full-wave rectification which further reduces arti(cid:173)
`effecting full-Wave recti?cation Which further reduces arti
`facts. Since the noise elements are determined within con(cid:173)
`facts. Since the noise elements are determined Within con
`tinuous speech segments, the noise is canceled from the
`tinuous speech segments, the noise is canceled from the
`audio signal nearly continuously thereby providing excellent
`audio signal nearly continuously thereby providing excellent
`noise cancellation characteristics. Residual noise reduction
`noise cancellation characteristics. Residual noise reduction
`reduces the residual noise remaining after noise cancella
`reduces the residual noise remaining after noise can cella -
`tion. Implementation may be effected in various noise can(cid:173)
`tion. Implementation may be effected in various noise can
`celing schemes including adaptive beamforming and noise
`celing schemes including adaptive beamforming and noise
`cancellation using computer program applications installed
`cancellation using computer program applications installed
`as software or hardware.
`as softWare or hardWare.
`
`(List continued on next page.)
`(List continued on next page.)
`
`47 Claims, 10 Drawing Sheets
`47 Claims, 10 Drawing Sheets
`
`202
`202
`
`R01) IE
`R(O) 1(0)
`'
`
`204
`204
`P
`R(n) I(n) ~-,----.~:W;;;;':;;;R(;;W~
`iY(n)=MaX[R(n)J(n)]
`R(n) |(n)
`V
`‘ +O.4’Min[R(n),|(n)]
`
`200 (114)
`
`206
`206
`
`Y(n)=
`1l3[Y(n-1)+Y(n)+Y(n+1)]
`
`208
`208
`P
`‘ Y(n)=
`Y(n),*o.3+Y(n),_1*0.7
`
`__
`
`210
`Subtraction - Noise
`
`212 (300)
`
`Process
`
`Estimation
`
`‘Fme Domain
`Time Domain
`214'V Input Signal
`214” InputSignal
`
`- OutputTo
`IFFT
`
`216
`216
`
`218
`
`Noise Processing
`Noise Processing
`
`RTL345-1_1001-0001
`
`

`
`US 6,363,345 BI
`US 6,363,345 B1
`Page 2
`Page 2
`
`U.S. PATENT DOCUMENTS
`US. PATENT DOCUMENTS
`
`3,170,046
`3,170,046 A
`3,247,925
`3,247,925 A
`3,262,521
`3,262,521 A
`3,298,457
`3,298,457 A
`3,330,376
`3,330,376 A
`3,394,226
`3,394,226 A
`3,416,782
`3,416,782 A
`3,422,921
`3,422,921 A
`3,562,089
`3,562,089 A
`3,702,644
`3,702,644 A
`3,830,988
`3,830,988 A
`3,889,059
`3,889,059 A
`3,890,474
`3,890,474 A
`4,068,092
`4,068,092 A
`4,122,303
`4,122,303 A
`4,153,815
`4,153,815 A
`4,169,257
`4,169,257 A
`4,239,936
`4,239,936 A
`4,241,805
`4,241,805 A
`4,243,117
`4,243,117 A
`4,261,708
`4,261,708 A
`4,321,970
`4,321,970 A
`4,334,740
`4,334,740 A
`4,339,018
`4,339,018 A
`4,363,007
`4,363,007 A
`4,409,435
`4,409,435 A
`4,417,098
`4,417,098 A
`4,433,435
`4,433,435 A
`4,442,546
`4,442,546 A
`4,453,600
`4,453,600 A
`4,455,675
`4,455,675 A
`4,459,851
`4,459,851 A
`4,461,025
`4,461,025 A
`4,463,222 A
`4,463,222
`4,473,906 A
`4,473,906
`4,477,505
`4,477,505 A
`4,489,441 A
`4,489,441
`4,490,841 A
`4,490,841
`4,494,074 A
`4,494,074
`4,495,643
`4,495,643 A
`4,517,415
`4,517,415 A
`4,527,282
`4,527,282 A
`4,530,304
`4,530,304 A
`4,539,708
`4,539,708 A
`4,559,642
`4,559,642 A
`4,562,589
`4,562,589 A
`4,566,118
`4,566,118 A
`4,570,155
`4,570,155 A
`4,581,758
`4,581,758 A
`4,589,136
`4,589,136 A
`4,589,137
`4,589,137 A
`4,600,863 A
`4,600,863
`4,622,692 A
`4,622,692
`4,628,529
`4,628,529 A
`4,630,302 A
`4,630,302
`4,630,304 A
`4,630,304
`4,636,586
`4,636,586 A
`4,649,505
`4,649,505 A
`4,653,102
`4,653,102 A
`4,653,606
`4,653,606 A
`4,654,871
`4,654,871 A
`4,658,426
`4,658,426 A
`4,672,674 A
`4,672,674
`4,683,010 A
`4,683,010
`4,696,043 A
`4,696,043
`4,718,096 A
`4,718,096
`4,731,850
`4,731,850 A
`4,736,432 A
`4,736,432
`4,741,038 A
`4,741,038
`4,750,207
`4,750,207 A
`
`2/1965
`2/1965 Leale
`Leale
`4/1966 Warnaka
`Warnaka
`4/1966
`7/1966 Warnaka
`Warnaka
`7/1966
`1/1967 Warnaka
`Warnaka
`1/1967
`7/1967 Warnaka
`Warnaka
`7/1967
`7/1968 Andrews, Jr.
`7/1968
`Andrews, Jr.
`12/1968 Warnaka
`Warnaka
`12/1968
`1/1969 Warnaka
`Warnaka
`1/1969
`2/1971 Warnaka et al.
`2/1971
`Warnaka et al.
`11/1972 Fowler et al.
`11/1972
`Fowler et al.
`8/1974 Mol et al.
`8/1974
`M01 et al.
`Thompson et al.
`6/1975
`6/1975 Thompson et al.
`Glicksberg
`6/1975
`6/1975 Glicksberg
`1/1978 Ikoma et al.
`1/1978
`Ikoma et al.
`Chaplin et al.
`10/1978 Chaplin et al.
`10/1978
`Chaplin et al.
`5/1979
`5/1979 Chaplin et al.
`9/1979 Smith
`Smith
`9/1979
`12/1980 Sakoe
`Sakoe
`12/1980
`12/1980 Chance, Jr.
`12/1980
`Chance, Jr.
`1/1981 Warnaka
`Warnaka
`1/1981
`Gallagher
`4/1981 Gallagher
`4/1981
`Thigpen
`3/1982 Thigpen
`3/1982
`Wray
`6/1982 Wray
`6/1982
`7/1982 Warnaka
`Warnaka
`7/1982
`12/1982 Haramoto et al.
`12/1982
`Haramoto et al.
`10/1983 Ono
`10/1983
`Ono
`Chaplin et al.
`11/1983 Chaplin et al.
`11/1983
`2/1984 David
`David
`2/1984
`Ishigaki
`4/1984 Ishigaki
`4/1984
`Thigpen
`6/1984 Thigpen
`6/1984
`6/1984 Bose et al.
`6/1984
`Bose et al.
`7/1984 Crostack
`Crostack
`7/1984
`7/1984 Franklin
`Franklin
`7/1984
`7/1984 Poradowski
`Poradowski
`7/1984
`9/1984 Warnaka et al.
`9/1984
`Warnaka et al.
`10/1984 Warnaka
`Warnaka
`10/1984
`Chaplin et al.
`12/1984 Chaplin et al.
`12/1984
`Chaplin et al.
`12/1984 Chaplin et al.
`12/1984
`1/1985 Bose
`1/1985
`Bose
`1/1985 Orban
`1/1985
`Orban
`5/1985 Laurence
`5/1985
`Laurence
`Chaplin et al.
`7/1985 Chaplin et al.
`7/1985
`7/1985 Gardos
`7/1985
`Gardos
`9/1985 Norris
`9/1985
`Norris
`Miyaji et al.
`12/1985 Miyaji et al.
`12/1985
`12/1985 Warnaka et al.
`12/1985
`Warnaka et al.
`Chaplin et al.
`1/1986 Chaplin et al.
`1/1986
`2/1986 Skarman et al.
`2/1986
`Skarman et al.
`4/1986 Coker et al.
`4/1986
`Coker et al.
`Poldy et al.
`5/1986 Poldy et al.
`5/1986
`5/1986 Miller
`5/1986
`Miller
`Chaplin et al.
`7/1986 Chaplin et al.
`7/1986
`11/1986 Cole
`Cole
`11/1986
`12/1986 Borth et al.
`12/1986
`Borth et al.
`Kryter
`12/1986 Kryter
`12/1986
`12/1986 Borth et al.
`12/1986
`Borth et al.
`1/1987 Schiff
`Schiff
`1/1987
`3/1987 Zinser, Jr. et al.
`3/1987
`Zinser, Jr. et al.
`3/1987 Hansen
`3/1987
`Hansen
`Flanagan
`3/1987 Flanagan
`3/1987
`Chaplin et al.
`3/1987 Chaplin et al.
`3/1987
`4/1987 Chabries et al.
`4/1987
`Chabries et al.
`Clough et al.
`6/1987 Clough et al.
`6/1987
`7/1987 Hartmann
`7/1987
`Hartmann
`9/1987 Iwahara et al.
`9/1987
`IWahara et al.
`1/1988 Meisel
`Meisel
`1/1988
`3/1988 Levitt et al.
`3/1988
`Levitt et al.
`4/1988 Cantrell
`Cantrell
`4/1988
`4/1988 Elko et al.
`4/1988
`Elko et al.
`6/1988 Gebert et al.
`6/1988
`Gebert et al.
`
`4,752,961
`4,752,961 A
`4,769,847
`4,769,847 A
`4,771,472
`4,771,472 A
`4,783,798
`4,783,798 A
`4,783,817
`4,783,817 A
`4,783,818
`4,783,818 A
`4,791,672
`4,791,672 A
`4,802,227
`4,802,227 A
`4,811,404
`4,811,404 A
`4,833,719
`4,833,719 A
`4,837,832
`4,837,832 A
`4,847,897
`4,847,897 A
`4,862,506
`4,862,506 A
`4,878,188
`4,878,188 A
`4,908,855
`4,908,855 A
`4,910,718
`4,910,718 A
`4,910,719
`4,910,719 A
`4,928,307
`4,928,307 A
`4,930,156
`4,930,156 A
`4,932,063
`4,932,063 A
`4,937,871
`4,937,871 A
`4,947,356
`4,947,356 A
`4,951,954
`4,951,954 A
`4,955,055
`4,955,055 A
`4,956,867
`4,956,867 A
`4,959,865
`4,959,865 A
`4,963,071
`4,963,071 A
`4,965,834
`4,965,834 A
`4,977,600
`4,977,600 A
`4,985,925
`4,985,925 A
`4,991,433
`4,991,433 A
`5,001,763
`5,001,763 A
`5,010,576
`5,010,576 A
`5,018,202
`5,018,202 A
`5,023,002
`5,023,002 A
`5,029,218
`5,029,218 A
`5,046,103
`5,046,103 A
`5,052,510
`5,052,510 A
`5,070,527
`5,070,527 A
`5,075,694
`5,075,694 A
`5,086,385
`5,086,385 A
`5,086,415
`5,086,415 A
`5,091,954
`5,091,954 A
`5,097,923
`5,097,923 A
`5,105,377
`5,105,377 A
`5,117,461
`5,117,461 A
`5,121,426
`5,121,426 A
`5,125,032
`5,125,032 A
`5,126,681
`5,126,681 A
`5,133,017
`5,133,017 A
`5,134,659
`5,134,659 A
`5,138,663
`5,138,663 A
`5,138,664
`5,138,664 A
`5,142,585
`5,142,585 A
`5,192,918
`5,192,918 A
`5,208,864
`5,208,864 A
`5,209,326
`5,209,326 A
`5,212,764
`5,212,764 A
`5,219,037
`5,219,037 A
`5,226,077
`5,226,077 A
`5,226,087
`5,226,087 A
`5,241,692
`5,241,692 A
`5,251,263
`5,251,263 A
`5,251,863
`5,251,863 A
`5,260,997
`5,260,997 A
`5,272,286
`5,272,286 A
`5,276,740
`5,276,740 A
`5,311,446
`5,311,446 A
`5,311,453
`5,311,453 A
`5,313,555
`5,313,555 A
`5,313,945
`5,313,945 A
`
`6/1988 Kahn
`Kahn
`6/1988
`Taguchi
`9/1988 Taguchi
`9/1988
`9/1988 Williams, III et al.
`9/1988
`Williams, III et al.
`11/1988 Leibholz et al.
`11/1988
`LeibholZ et al.
`11/1988 Hamada et al.
`11/1988
`Hamada et al.
`Graupe et al.
`11/1988 Graupe et al.
`11/1988
`Nunley et al.
`12/1988 Nunley et al.
`12/1988
`1/1989 Elko et al.
`1/1989
`Elko et al.
`3/1989 Vilmur et al.
`3/1989
`Vilmur et al.
`5/1989
`5/1989 Carme et al.
`Carme et al.
`6/1989 Fanshel
`Fanshel
`6/1989
`7/1989 Means
`7/1989
`Means
`Landgarten et al.
`8/1989 Landgarten et al.
`8/1989
`Ziegler et al.
`10/1989 Ziegler et al.
`10/1989
`Ohga et al.
`3/1990 Ohga et al.
`3/1990
`3/1990 Horn
`3/1990
`Horn
`3/1990 Thubert
`Thubert
`3/1990
`Lynn
`5/1990
`5/1990 Lynn
`5/1990
`5/1990 Norris
`Norris
`6/1990 Nakamura
`Nakamura
`6/1990
`6/1990 Hattori
`Hattori
`6/1990
`8/1990 Elliott et al.
`8/1990
`Elliott et al.
`8/1990 MacNeill
`MacNeill
`8/1990
`Fujisaki et al.
`9/1990 Fujisaki et al.
`9/1990
`9/1990 Zarek et al.
`9/1990
`Zarek et al.
`9/1990 Stettiner et al.
`9/1990
`Stettiner et al.
`10/1990 Larwin et al.
`10/1990
`Larwin et al.
`10/1990 Miller
`Miller
`10/1990
`Ziegler
`12/1990 Ziegler
`12/1990
`Langberg et al.
`1/1991 Langberg et al.
`1/1991
`2/1991 Warnaka et al.
`2/1991
`Warnaka et al.
`Moseley
`3/1991 Moseley
`3/1991
`4/1991 Hill
`Hill
`4/1991
`5/1991 Takahashi et al.
`5/1991
`Takahashi et al.
`6/1991 Schweizer et al.
`6/1991
`SchWeiZer et al.
`Nagayasu
`7/1991 Nagayasu
`7/1991
`9/1991 Warnaka et al.
`9/1991
`Warnaka et al.
`10/1991 Gossman
`10/1991
`Gossman
`Lynn
`12/1991 Lynn
`12/1991
`Donnangelo et al.
`12/1991 Donnangelo et al.
`12/1991
`2/1992 Launey et al.
`Launey et al.
`2/1992
`2/1992 Takahashi et al.
`2/1992
`Takahashi et al.
`2/1992 Sasaki et al.
`2/1992
`Sasaki et al.
`Ziegler et al.
`3/1992 Ziegler et al.
`3/1992
`Ziegler, Jr.
`4/1992 Ziegler, Jr.
`4/1992
`Moseley
`5/1992 Moseley
`5/1992
`6/1992 Bavmhauer
`Bavmhauer
`6/1992
`6/1992 Meister et al.
`6/1992
`Meister et al.
`6/1992 Ziegler, Jr. et al.
`Ziegler, Jr. et al.
`6/1992
`7/1992 Cain et al.
`7/1992
`Cain et al.
`Moseley
`7/1992 Moseley
`7/1992
`Moseley
`8/1992 Moseley
`8/1992
`8/1992 Kimura et al.
`8/1992
`Kimura et al.
`Taylor
`8/1992 Taylor
`8/1992
`Sugiyama
`3/1993 Sugiyama
`3/1993
`5/1993 Kaneda
`5/1993
`Kaneda
`Harper
`5/1993 Harper
`5/1993
`Ariyoshi
`5/1993 Ariyoshi
`5/1993
`6/1993 Smith et al.
`6/1993
`Smith et al.
`7/1993 Lynn et al.
`Lynn et al.
`7/1993
`7/1993 Ono
`7/1993
`Ono
`8/1993 Harrison et al.
`8/1993
`Harrison et al.
`10/1993 Andrea et al.
`10/1993
`Andrea et al.
`10/1993 Gossman et al.
`10/1993
`Gossman et al.
`11/1993 Gattey et al.
`Gattey et al.
`11/1993
`12/1993 Cain et al.
`12/1993
`Cain et al.
`1/1994 Inanaga et al.
`Inanaga et al.
`1/1994
`5/1994 Ross et al.
`5/1994
`Ross et al.
`Denenberg et al.
`5/1994 Denenberg et al.
`5/1994
`Kamiya
`5/1994 Kamiya
`5/1994
`5/1994 Friedlander
`5/1994
`Friedlander
`
`RTL345-1_1001-0002
`
`

`
`US 6,363,345 BI
`US 6,363,345 B1
`Page 3
`Page 3
`
`5/1994 Gossman et al.
`5,315,661 A
`5/1994 Gossman et al.
`5,315,661 A
`6/1994 Hunt
`5,319,736 A
`6/1994 Hunt
`5,319,736 A
`7/1994 Stites, III
`5,327,506 A
`7/1994 Stites, 111
`5,327,506 A
`7/1994 Gossman et al.
`5,332,203 A
`7/1994 Gossman et al.
`5,332,203 A
`8/1994 Addeo et al.
`5,335,011 A
`8/1994 Addeo et al.
`5,335,011 A
`9/1994 Harper
`5,348,124 A
`9/1994 Harper
`5,348,124 A
`10/1994 Irissou et al.
`5,353,347 A
`5,353,347 A 10/1994 Irissou et al.
`5,353,376 A
`10/1994 Oh et al.
`5,353,376 A 10/1994 on et al.
`5,361,303 A
`11/1994 Eatwell
`5,361,303 A 11/1994 Eatwell
`5,365,594 A
`11/1994 Ross et al.
`5,365,594 A 11/1994 Ross et al.
`5,375,174 A
`12/1994 Denenberg
`5,375,174 A 12/1994 Denenberg
`5,381,473 A
`1/1995 Andrea et al.
`5,381,473 A
`1/1995 Andrea et al.
`5,381,481 A
`1/1995 Gammie et al.
`5,381,481 A
`1/1995 Gammie et al.
`5,384,843 A
`1/1995 Masuda er a1,
`5,384,843 A
`1/1995 Masuda et al.
`5,402,497 A
`3/1995 Nishimoto et al.
`5,402,497 A
`3/1995 Nishimoto et al.
`5,412,735 A
`5/1995 Engebretson et al.
`5,412,735 A
`5/1995 Engebretson er a1,
`5,414,769 A
`5/1995 Gattey et al.
`5,414,769 A
`5/1995 Gattey et al.
`5,414,775 A
`5/1995 Scribner et al.
`5,414,775 A
`5/1995 Scribner et al.
`5,416,845 A
`5/1995 shen
`5,416,845 A
`5/1995 Shen
`5,416,847 A
`5/1995 B016
`5,416,847 A
`5/1995 Boze
`5,416,887 A
`5/1995 Shimada
`5,416,887 A
`5/1995 Shimada
`5,418,857 A
`5/1995 Eatwell
`5,418,857 A
`5/1995 Eatwell
`5,423,523 A
`6/1995 Gossman et al.
`5,423,523 A
`6/1995 Gossman et al.
`5,431,008 A
`7/1995 Ross et a1_
`5,431,008 A
`7/1995 Ross et al.
`5,432,859 A
`7/1995 Yang et a1,
`5,432,859 A
`7/1995 Yang et al.
`5,434,925 A
`7/1995 Nadim
`5,434,925 A
`7/1995 Nadim
`5,440,642 A
`8/1995 Denenberg et al.
`5,440,642 A
`8/1995 Denenberg er a1,
`5,448,637 A
`9/1995 Yamaguchi et al.
`5,448,637 A
`9/1995 Yamaguchi et al.
`5,452,361 A
`9/1995 Jones
`5,452,361 A
`9/1995 Jones
`5,457,749 A 10/1995 Cain er a1,
`5,457,749 A
`10/1995 Cain et al.
`5,469,087 A
`11/1995 Eatwell
`5,469,087 A 11/1995 Eatwell
`5,471,106 A
`11/1995 Curtis et al.
`5,471,106 A 11/1995 Curtis et al.
`5,471,538 A 11/1995 Sasaki et a1.
`5,471,538 A
`11/1995 Sasaki et al.
`5,473,214 A
`12/1995 Hildebrand
`5,473,214 A 12/1995 Hildebrand
`5,473,701 A
`12/1995 Cezanee et al.
`5,473,701 A 12/1995 CeZanee et al.
`5,473,702 A
`12/1995 Yoshida et al.
`5,473,702 A 12/1995 Yoshida et al.
`5,475,761 A 12/1995 Eatwell
`5,475,761 A
`12/1995 Eatwell
`5,479,562 A * 12/1995 Fielder et al.
`.............. 704/229
`5,479,562 A * 12/1995 Fielder et a1. ............ .. 704/229
`5,481,615 A
`1/1996 Eatwell et al.
`5,481,615 A
`1/1996 Eatwell er a1,
`5,485,515 A
`1/1996 Allen et al.
`5,485,515 A
`1/1996 Allen et a1.
`5,493,615 A
`2/1996 Burke et al.
`5,493,615 A
`2/1996 Burke er a1,
`5,502,869 A
`4/1996 Smith et al.
`5,502,869 A
`4/1996 Smith et al.
`5,511,127 A
`4/1996 Warnaka
`5,511,127 A
`4/1996 Wamaka
`5,511,128 A
`4/1996 Lindeman
`5,511,128 A
`4/1996 Lindeman
`5,515,378 A
`5/1996 Roy, III et al.
`5,515,378 A
`5/1996 Roy, III et a1.
`5,524,056 A
`6/1996 Killion et al.
`5,524,056 A
`6/1996 Killion et al.
`5,524,057 A
`6/1996 Akiho et al.
`5,524,057 A
`6/1996 Akiho et a1.
`5,526,432 A
`6/1996 Denenberg
`5,526,432 A
`6/1996 Denenberg
`5,546,090 A
`8/1996 Roy, III et al.
`5,546,090 A
`8/1996 Roy, III et a1.
`5,546,467 A
`8/1996 Denenberg
`5,546,467 A
`8/1996 Denenberg
`5,550,334 A
`8/1996 Langley
`5,550,334 A
`8/1996 Langley
`5,553,153 A
`9/1996 Eatwell
`5,553,153 A
`9/1996 Eatwell
`5,563,817 A
`10/1996 Ziegler et al.
`5,563,817 A 10/1996 Ziegler et a1.
`5,568,557 A
`10/1996 Ross et al.
`5,568,557 A 10/1996 Ross et a1.
`5,581,620 A
`12/1996 Brandstein et al.
`5,581,620 A 12/1996 Brandstein et a1.
`5,592,181 A
`1/1997 Cai et al.
`5,592,181 A
`1/1997 Cai et a1.
`5,592,490 A
`1/1997 Barratt et al.
`5,592,490 A
`1/1997 Barratt et a1.
`5,600,106 A
`2/1997 Langley
`5,600,106 A
`2/1997 Langley
`5,604,813 A
`2/1997 Evans et al.
`5,604,813 A
`2/1997 Evans et a1.
`5,615,175 A
`3/1997 Cater et al.
`5,615,175 A
`3/1997 Cater et a1.
`5,617,479 A
`4/1997 Hildebrand et al.
`5,617,479 A
`4/1997 Hildebrand et a1.
`5,619,020 A
`4/1997 Jones et al.
`5,619,020 A
`4/1997 Jones et a1.
`5,621,656 A
`4/1997 Langley
`5,621,656 A
`4/1997 Langley
`5,625,697 A
`4/1997 Bowen et al.
`5,625,697 A
`4/1997 Bowen et a1.
`5,625,880 A
`4/1997 Goldburg et al.
`5,625,880 A
`4/ 1997 Goldburg et a1.
`5,627,746 A
`5/1997 Ziegler, Jr. et al.
`5,627,746 A
`5/1997 Ziegler, Jr. et a1.
`5,627,799 A
`5/1997 Hoshuyama
`5,627,799 A
`5/1997 Hoshuyama
`5,638,022 A
`6/1997 Eatwell
`5,638,022 A
`6/1997 Eatwell
`5,638,454 A
`6/1997 Jones et al.
`5,638,454 A
`6/1997 Jones et a1.
`5,638,456 A
`6/1997 Conley et al.
`5,638,456 A
`6/1997 Conley et a1.
`5,642,353 A
`6/1997 Roy, III et al.
`5,642,353 A
`6/1997 Roy, III et a1.
`
`7/1997 Ikeda
`5,644,641 A
`7/1997 Ikeda
`5,644,641 A
`7/1997 Gifford et al.
`5,649,018 A
`7/1997 Gifford et al.
`5,649,018 A
`7/1997 Eatwell
`5,652,770 A
`7/1997 Eatwell
`5,652,770 A
`7/1997 Ross et al.
`5,652,799 A
`7/1997 Ross et al.
`5,652,799 A
`8/1997 Crow
`5,657,393 A
`8/1997 Crow
`5,657,393 A
`9/1997 Chu et al.
`5,664,021 A
`9/1997 Chu et al.
`5,664,021 A
`9/1997 Obashi
`5,668,747 A
`9/1997 Obashi
`5,668,747 A
`5,668,927 A * 9/1997 Chan et al. ................. 704/240
`5,668,927 A * 9/1997 Chan et al. ............... .. 704/240
`5,673,325 A
`9/1997 Andrea et al.
`5,673,325 A
`9/1997 Andrea et al.
`5,676,353 A
`10/1997 Jones et al.
`5,676,353 A 10/1997 Jones et al.
`5,689,572 A
`11/1997 Ohki et al.
`5,689,572 A 11/1997 Ohki et al.
`5,692,053 A
`11/1997 Fuller et al.
`5,692,053 A 11/1997 Fuller et al.
`5,692,054 A
`11/1997 Parrella et al.
`5,692,054 A 11/1997 Parrella et al.
`5,699,436 A
`12/1997 Claybaugh et al.
`5,699,436 A 12/1997 Claybaugh et al.
`5,701,344 A
`12/1997 Wakui
`5,701,344 A 12/1997 Waklli
`5,706,394 A * 1/1998 Wynn ......................... 704/219
`5,706,394 A * 1/1998 Wynn ....................... .. 704/219
`5,715,319 A
`2/1998 Chu
`5,715,319 A
`2/1998 Chu
`5,715,321 A
`2/1998 Andrea et al.
`5,715,321 A
`2/1998 Andrea et 91
`5,719,945 A
`2/1998 Fuller et al.
`5,719,945 A
`2/1998 Fuller et al.
`5,724,270 A
`3/1998 Posch
`5,724,270 A
`3/1998 Posch
`5,727,073 A
`3/1998 Ikeda
`5,727,073 A
`3/1998 Ikeda
`5,732,143 A
`3/1998 Andrea et al.
`5,732,143 A
`3/1998 Andrea etal.
`5,745,581 A
`4/1998 Eatwell et al.
`5,745,581 A
`4/1998 EatWell 6t 61
`5,748,749 A
`5/1998 Miller et al.
`5,748,749 A
`5/1998 Miller et al.
`5,768,473 A
`6/1998 Eatwell et al.
`5,768,473 A
`6/1998 EatWell et al.
`5,774,859 A
`6/1998 Houser et al.
`5,774,859 A
`6/1998 Houser etal.
`5,787,259 A * 7/1998 Haroun et al. .............. 709/253
`5,787,259 A * 7/1998 Haroun et al. ............ .. 709/253
`5,798,983 A
`8/1998 Kuhn et al.
`5,798,983 A
`8/1998 Kuhn et 91
`5,812,682 A
`9/1998 Ross et al.
`5,812,682 A
`9/1998 Ross et al.
`5,815,582 A
`9/1998 Claybaugh et al.
`5,815,582 A
`9/1998 Claybaugh et al.
`5,818,948 A * 10/1998 Gulick ........................ 381/77
`5,818,948 A * 10/1998 Gulick ...................... .. 381/77
`5,825,897 A
`10/1998 Andrea et al.
`5,825,897 A 10/1998 Andrea et a1.
`5,825,898 A
`10/1998 Marash
`5,825,898 A 10/1998 Marash
`5,828,768 A
`10/1998 Eatwell et al.
`5,828,768 A 10/1998 EatWell et al.
`5,835,608 A
`11/1998 Warnaka et al.
`5,835,608 A 11/1998 Warnaka 6t 61
`5,838,805 A
`11/1998 Warnaka et al.
`5,838,805 A 11/1998 Warnaka et al
`5,874,918 A
`3/1999 Czarnecki et al.
`5,874,918 A
`3/1999 CZarneckietal.
`5,909,495 A
`6/1999 Andrea
`5,909,495 A
`6/1999 Andrea
`5,914,877 A * 6/1999 Gulick .................. 364/400.01
`5,914,877 A * 6/1999 Gulick ................ .. 364/400.01
`5,914,912 A
`6/1999 Yang
`5,914,912 A
`6/1999 Yang
`5,995,150 A * 11/1999 Hsieh et al.
`................ 348/409
`5,995,150 A * 11/1999 Hsieh et al. .............. .. 348/409
`
`FOREIGN PATENT DOCUMENTS
`FOREIGN PATENT DOCUMENTS
`
`EP
`EP
`EP
`EP
`EP
`EP
`EP
`EP
`FR
`FR
`GB
`GB
`GB
`GB
`GB
`GB
`GB
`GB
`GB
`GB
`GB
`GB
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`WO
`W0
`WO
`W0
`WO
`W0
`WO
`W0
`WO
`W0
`WO
`W0
`WO
`W0
`
`2/1994
`0583900 A1
`2/1994
`0 583 900 A1
`5/1994
`0595457 A1
`5/1994
`0 595 457 A1
`7/1996
`0721 251
`7/1996
`0 721 251
`11/1996
`0724415
`11/1996
`0 724 415
`10/1976
`2305909
`10/1976
`2305909
`1 160431
`8/1969
`8/1969
`1 160 431
`9/1972
`1 289 993
`9/1972
`1 289 993
`12/1974
`1378294
`12/1974
`1 378 294
`9/1986
`2172 769 A
`9/1986
`2 172 769 A
`7/1991
`2239971 B
`7/1991
`2 239 971 B
`11/1995
`2289593 A
`2 289 593 A 11/1995
`56-89194
`7/1981
`56-89194
`7/1981
`59-64994
`4/1984
`59-64994
`4/1984
`62-189898
`8/1987
`62-189898
`8/1987
`1-149695
`6/1989
`1-149695
`6/1989
`1-314098
`12/1989
`1-314098
`12/1989
`2-070152
`3/1990
`2-070152
`3/1990
`3-169199
`7/1991
`3-169199
`7/1991
`3-231599
`10/1991
`3-231599
`10/1991
`4-16900
`1/1992
`4-16900
`1/1992
`WO 88/09512
`12/1988
`WO 88/09512
`12/1988
`WO 92/05538
`4/1992
`WO 92/05538
`4/1992
`WO 92/17019
`10/1992
`WO 92/17019
`10/1992
`WO 94/16517
`7/1994
`WO 94/16517
`7/1994
`WO 95/08906
`3/1995
`WO 95/08906
`3/1995
`WO 96/15541
`5/1996
`WO 96/15541
`5/1996
`WO 97/23068
`6/1997
`WO 97/23068
`6/1997
`
`RTL345-1_1001-0003
`
`

`
`US 6,363,345 BI
`US 6,363,345 B1
`Page 4
`Page 4
`
`OlliER PUBLICATIONS
`OTHER PUBLICATIONS
`
`Edward J. Foster, "Switched on Silence", Popular Science,
`Edward J. Foster, “Switched on Silence”, Popular Science,
`1994, p. 33.
`1994, p. 33.
`Kuo, Automatic Control of Systems, pp. 504—585.
`Kuo, Automatic Control of Systems, pp. 504-585.
`Luenberger, Optimization by Vector Space Method, pp.
`Luenberger, Optimization by Vector Space Method, pp.
`134-138.
`134—138.
`Ogata, Modern Control Engineering, pp. 474—508.
`Ogata, Modern Control Engineering, pp. 474-508.
`Oppenheirn Schafer, Digital Signal Processing (Prentice
`Oppenheim Schafer, Digital Signal Processing (Prentice
`Hall) pp. 542—545.
`Hall) pp. 542-545.
`P.P. Vaidyanathan, “Multirate Digital Filters, Filter Banks,
`P.P. Vaidyanathan, "Multirate Digital Filters, Filter Banks,
`Polyphase Networks, and Applications; A Tutorial,” IEEE
`Polyphase Networks, and Applications; A Tutorial," IEEE
`Proc., vol. 78, No.1, Jan. 1990.
`Proc., vol. 78, No. 1, Jan. 1990.
`P.P. Vaidyanathan, "Quadrature Mirror Filter Banks,
`PP. Vaidyanathan, “Quadrature Mirror Filter Banks,
`M-band Extensions and Perfect-Reconstruction Tech(cid:173)
`M—band Extensions and Perfect—Reconstruction Tech
`niques,” IEEE ASSP Magazine, Jul. 1987, pp. 4—20.
`niques," IEEE ASSP Magazine, Jul. 1987, pp. 4-20.
`Rabiner et aI., IEEE Trans. on Acous., vol. ASSP-24, No.5,
`Rabiner et al., IEEE Trans. on Acous., vol. ASSP—24, No. 5,
`Oct. 1976, pp. 399-418.
`Oct. 1976, pp. 399—418.
`
`Rubiner et al., Digital Processing of Speech Signals (Pren
`Rubiner et aI., Digital Processing of Speech Signals (Pren(cid:173)
`tice Hall, 1978) pp. 130-135.
`tice Hall, 1978) pp. 130—135.
`Sapontis, Probability, Lambda Variables and Structural
`Sapo ntis, Probability, Lambda Variables and Structural
`Processes, pp. 467-474.
`Processes, pp. 467—474.
`Scott C. Douglas, “A Family of NorrnaliZed LMS Algo
`Scott C. Douglas, "A Family of Normalized LMS Algo(cid:173)
`rithms," IEEE Signal Proc. Letters, vol. 1, No.3, Mar. 1994.
`rithrns,” IEEE Signal Proc. Letters, vol. 1, No. 3, Mar. 1994.
`Sewald et aI., "Application of ... Beamforming to Reject
`SeWald et al., “Application of .
`.
`. Bearnforrning to Reject
`Turbulence Noise in Airducts," IEEE ICASSP vol. 5, No.
`Turbulence Noise in Airducts,” IEEE ICASSP vol. 5, No.
`CONF-21, May 7, 1996, pp. 2734-2737.
`CONF—21, May 7, 1996, pp. 2734—2737.
`White, Moving—Coil Earphone Design, 1963, pp. 188—194.
`White, Moving-Coil Earphone Design, 1963, pp. 188-194.
`WidroW et al., “Adaptive Noise Canceling: Principles and
`Widrow et aI., "Adaptive Noise Canceling: Principles and
`Applications,” Proc. IEEE, vol. 63, No. 12, Dec. 1975, pp.
`Applications," Proc. IEEE, vol. 63, No. 12, Dec. 1975, pp.
`1692-1716.
`1692—1716.
`Youla et aI., IEEE Trans. on Acous., vol. MI-1, No.2, Oct.
`Youla et al., IEEE Trans. on Acous., vol. MI—1, No. 2, Oct.
`1982, pp. 81-101.
`1982, pp. 81—101.
`* cited by examiner
`* cited by eXarniner
`
`RTL345-1_1001-0004
`
`

`
`I--"
`~
`(I)
`~
`~
`~
`~
`0'1
`rJ'l
`
`e
`
`'""'" c
`'""'" o ....,
`~ .....
`'JJ. =(cid:173)~
`
`N
`C
`C
`N
`~~
`N
`:"l
`~
`~
`
`~ = .....
`~ .....
`~
`•
`rJl
`d •
`
`FIG. 1
`
`Spectral Subtraction System
`
`118
`~
`
`Samples
`Output
`
`116
`(
`
`100
`
`114
`(
`
`1-1 __ _
`
`Sum
`IFFT HAnd
`Overlap
`
`112 (200)
`
`(
`
`110
`7
`
`H
`
`Processing
`
`512PointHNoise
`
`'---~~I FFT
`
`Window
`Hanning
`By
`Multiply
`(
`108
`Coefficients
`Shading
`
`106
`
`104
`
`samples~
`Input
`~
`102
`
`256 History
`Point with
`256 New
`Combine
`
`Data
`Input
`Collect
`
`RTL345-1_1001-0005
`
`

`
`I--"
`~
`(I)
`~
`~
`~
`~
`0'1
`rJ'l
`
`US 6,363,345 B1
`
`e
`
`'""" c
`o .....,
`N
`~ .....
`'JJ. =(cid:173)~
`
`Sheet 2 0f 10
`
`N
`C
`C
`N
`~~
`N
`:"l
`~
`~
`
`Mar. 26, 2002
`
`~ = .....
`~ .....
`~
`•
`rJl
`d •
`
`U.S. Patent
`
`632.6%
`
`Estimation
`Noise
`
`
`
`cozmEzwm 382m
`
`
`
`@202 , cotbmznsw
`
`-.
`
`..
`
`Noise Processing
`
`
`
`mEwwwooE @202
`
`FIG. 2
`
`N .UE
`
`
`EmEoQ wEc.
`2265 :35 \(wrm
`
`
`(300)
`
`
`
`608 N3.
`
`• 21:
`
`1Ir
`
`Y(n)t*0.3+Y(n)t_1 *0. 7
`Y(n)=
`
`2~8
`
`1/3[Y(n-1 )+Y(n)+Y(n+1)]
`Y(n)=
`>
`206
`
`~
`
`
`
`A A A wow 8.6. v8
`
`
`
`z 1552;; 75am:
`
`2(1)(114)
`
`:1: 08
`
`+O.4*Min[R(n),I(n)]
`Y(n)=Max[R(n),I(n)]
`
`.
`2~4
`
`E: EE
`
`R(n) I(
`
`6: 6E
`
`R(O) I(
`
`mom 2
`
`02
`
`218
`
`216
`
`.
`
`
`
`PUT: 380$
`
`-Process
`-Residual
`•
`Process
`210 •
`Subtraction
`>
`
`RTL345-1_1001-0006
`
`

`
`I--"
`~
`(I)
`~
`~
`~
`~
`0'1
`rJ'l
`
`US 6,363,345 B1
`
`e
`
`~
`
`'""'" c
`0 ....,
`~ .....
`'JJ. =-~
`
`Sheet 3 0f 10
`
`N
`C
`C
`N
`~~
`N
`:"l
`~
`~
`
`Mar. 26, 2002
`
`~ = .....
`~ .....
`~
`•
`rJl
`d •
`
`U.S. Patent
`
`Bin(n)
`For
`Level
`Noise
`<
`312
`
`FIG. 3
`
`m .9"
`
`Noise Estimation Process
`
`
`
`
`
`$805 cozmEzwm @202
`
`310
`
`308
`
`r---. O.05*New Oata+
`
`N(n)=
`
`Assm
`E @2630
`
`O.95*N(n)
`
`Discard
`4*Min]
`If[Y(n»
`+
`
`Every 5 Seconds
`Init With Future Min
`
`Every 5 Seconds
`Init With Y(n)
`
`r---
`
`rv306
`
`5 Sec
`Min Over
`Search For
`Current Minimum ~
`
`5 Sec
`Min Over
`Search For
`Future Minimum
`
`
`
`6m cogmww A w EEEEE 23:". wow
`
`.
`
`Em
`
`304
`
`300 (212)
`
`85 O8
`
`Y(n)
`
`Y(O)
`
`302
`
`RTL345-1_1001-0007
`
`

`
`I--"
`~
`(I)
`~
`~
`~
`~
`0'1
`rJ'l
`
`e
`
`~
`
`'""'" c
`o ....,
`~ .....
`'JJ. =(cid:173)~
`
`N
`C
`C
`N
`~~
`N
`:"l
`~
`~
`
`~ = .....
`~ .....
`~
`•
`rJl
`d •
`
`FIG. 4
`
`Subtraction Process
`
`Process
`Residual Noise
`QutTo
`
`~
`
`~
`
`Qut[1 (n )]=In [I (n )]*H (n)
`
`Out[R(n )]=In [R(n )]*H (n) tv 404
`
`In[l(n)]
`
`In[R(n)]
`
`IY(n)1
`
`iv402
`
`IIY(n)1 -N(n)1
`
`~ H(n) =
`
`Y(n)
`
`N(n)
`
`400 (210)
`
`RTL345-1_1001-0008
`
`

`
`u.s. Patent
`
`Mar. 26,2002
`
`Sheet 5 of 10
`
`US 6,363,345 BI
`
`o o
`
`LO
`
`N o
`LO
`>
`
`..c
`(J) U
`:s:
`U:!::
`0-
`~(f)
`
`c Oro rn
`E C
`o 02>
`ou)
`E ~
`0- C
`1---
`
`(J)-
`
`~..c
`o U
`LL
`(J)
`C
`oc%
`(J)
`
`C
`I
`~ C
`:::::l 0
`I--Z
`
`""'" o
`LO >
`
`I
`
`-- --
`-- --
`
`c
`0:::
`
`c
`
`(])
`()
`
`rJ) en
`o L-a..
`
`(])Ln
`rJ)
`•
`
`OC) z-
`
`LL
`
`m
`::J
`"U
`en
`(])
`0::
`
`RTL345-1_1001-0009
`
`

`
`I--"
`~
`(I)
`~
`~
`~
`~
`0'1
`rJ'l
`
`US 6,363,345 B1
`
`e
`
`~
`
`'""'" c
`0 ....,
`~ .....
`'JJ. =-~
`
`Sheet 6 0f 10
`
`~~
`N
`:"l
`~
`~
`
`~ = .....
`~ .....
`~
`•
`rJl
`d •
`
`U.S. Patent
`
`Mar. 26, 2002
`
`N c c
`
`N
`
`Residual Noise Process Alternative
`
`
`
`
`
`FIG.5A
`
`
`
`@2552? $321 $62 _m:_2wmm
`
`gm
`
`I(n)
`R(n)
`
`2:
`
`510
`
`Value
`Minimum
`With
`Replace
`
`:1
`
`I(n)
`R(n)
`
`comwawéoz
`
`Non-Speech
`Turn On For
`
`6m :0 EB.
`
`wcm
`
`I
`fv508
`
`:llfY(n) <
`
`4*N(n)
`
`N(n)
`Y(n)
`
`506
`
`RTL345-1_1001-0010
`
`

`
`u.s. Patent
`U.S. Patent
`
`Mar. 26, 2002
`Mar. 26,2002
`
`Sheet 7 of 10
`Sheet 7 0f 10
`
`US 6,363,345 BI
`US 6,363,345 B1
`
`Read Input
`Read Input
`Samples
`Samples
`
`600
`600
`
`602
`602
`
`Store Data in
`Store Data in
`Buffer
`Buffer
`
`Are 256
`New Points
`Accumulated
`
`No-......
`N0—>
`
`604
`
`,
`
`\
`
`608
`608
`
`I
`I
`\
`
`Stored Inputs
`Stored Inputs
`
`Yes
`Yes
`t
`+
`Move 512 Last
`Move 512 Last
`Points to Processing
`Points to Processing
`Buffer
`Buffer
`
`~ 606
`606
`
`v 610
`610
`
`Perform 512
`_______—> Perform 512
`Points FFT
`Poin