Paper No. __
`Filed: July 6, 2023
`
`UNITED STATES PATENT AND TRADEMARK OFFICE
`
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`
`
`
`
`
`LG ELECTRONICS INC.,
`Petitioner,
`v.
`JAWBONE INNOVATIONS, LLC,
`Patent Owner.
`
`IPR2023-01156
`U.S. Patent No. 8,326,611
`
`
`PETITION FOR INTER PARTES REVIEW
`OF CLAIMS 29-44 OF U.S. PATENT NO. 8,326,611
`
`
`
`
`
`
`
`
`
`
`
`

`

`Petition for Inter Partes Review of U.S. Patent No. 8,326,611
`
`TABLE OF CONTENTS
`
`I.
`
`II.
`
`REQUIREMENTS FOR IPR .......................................................................... 4
`A. Grounds for Standing ............................................................................ 4
`B.
`Challenge and Relief Requested ........................................................... 4
`C.
`Priority Date .......................................................................................... 5
`1.
`Dynamic Drinkware Analysis ..................................................... 6
`BACKGROUND ............................................................................................. 8
`A.
`The ‘611 Patent ..................................................................................... 8
`B.
`Prosecution History ............................................................................... 9
`C.
`Level of Ordinary Skill ....................................................................... 10
`D.
`Claim Construction ............................................................................. 10
`III. GROUND 1: Avendano ‘880 and Hou (Claims 29-31, 33-37, 41-44) ......... 10
`A. Avendano ‘880 Overview ................................................................... 10
`B. Hou Overview ..................................................................................... 16
`C.
`Combination of Avendano ‘880 and Hou ........................................... 19
`D.
`Claim 29 .............................................................................................. 34
`E.
`Claim 30 .............................................................................................. 51
`F.
`Claim 31 .............................................................................................. 53
`G.
`Claim 33 .............................................................................................. 54
`H.
`Claim 34 .............................................................................................. 61
`I.
`Claim 35 .............................................................................................. 62
`J.
`Claim 36 .............................................................................................. 64
`K.
`Claim 37 .............................................................................................. 66
`
`i
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`Petition for Inter Partes Review of U.S. Patent No. 8,326,611
`
`V.
`
`Claims 41 and 42 ................................................................................. 67
`L.
`M. Claim 43 .............................................................................................. 68
`N.
`Claim 44 .............................................................................................. 69
`IV. GROUND 2: Avendano ‘880, Hou, and Avendano ‘252 (Claims 32, 38-
`40) .................................................................................................................. 70
`A. Avendano ‘252 Overview ................................................................... 70
`B.
`Combination of Avendano ‘880, Hou, and Avendano ‘252 ............... 75
`C.
`Claim 32 .............................................................................................. 77
`D.
`Claim 38 .............................................................................................. 83
`E.
`Claim 39 .............................................................................................. 86
`F.
`Claim 40 .............................................................................................. 88
`INSTITUTION IS APPROPRIATE HERE .................................................. 91
`A.
`Two Substantive Petitions Were Necessary to Challenge All Claims
`of the’611 Patent ................................................................................. 91
`Co-Pending Litigation Does Not Warrant Discretionary Denial Under
`§ 314(A) (Fintiv) ................................................................................. 94
`1.
`Factor 1: Potential Stay ............................................................. 94
`2.
`Factor 2: Proximity of Trial to FWD ........................................ 94
`3.
`Factor 3: Investment in Parallel Proceeding ............................. 95
`4.
`Factor 4: Overlapping Issues .................................................... 96
`5.
`Factor 5: Parties in Parallel Proceedings .................................. 96
`6.
`Factor 6: Other Circumstances .................................................. 97
`The Existence of Previously Filed IPR Petitions Does Not Warrant
`Discretionary Denial (General Plastic) ............................................... 97
`D. Discretionary Denial Under § 325(D) is Also Not Appropriate ......... 98
`
`B.
`
`C.
`
`ii
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`Petition for Inter Partes Review of U.S. Patent No. 8,326,611
`
`VI. MANDATORY NOTICES UNDER 37 C.F.R § 42.8(a)(1) ......................... 99
`A.
`Real Party-In-Interest Under 37 C.F.R. § 42.8(b)(1) .......................... 99
`B.
`Related Matters Under 37 C.F.R. § 42.8(b)(2) ................................... 99
`C.
`Lead And Back-Up Counsel Under 37 C.F.R. § 42.8(b)(3) ............. 101
`D.
`Service Information ........................................................................... 102
`E.
`Payment of Fees Pursuant to 37 C.F.R. § 42.103 ............................. 102
`CERTIFICATE OF COMPLIANCE ..................................................................... 103
`
`
`
`
`
`iii
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`Petition for Inter Partes Review of U.S. Patent No. 8,326,611
`
`TABLE OF AUTHORITIES
`
`Pages(s):
`
`Cases:
`Amazon.com, Inc. v. Jawbone Innovations, LLC,
`IPR2023-00285, Paper 10 (P.T.A.B. June 7, 2023) ................................. 94
`Amazon.com, Inc. v. Jawbone Innovations, LLC,
`IPR2023-00285, Paper 11 (P.T.A.B. June 7, 2023) ................................. 96
`Apple Inc. v. Fintiv, Inc.,
`IPR2020-00019, Paper 11 (P.T.A.B. Mar. 20, 2020) ......................... 94, 97
`Cal. Inst. of Tech. v. Broadcom Ltd.,
`25 F.4th 976 (Fed. Cir. 2022) ................................................................... 96
`Central Security Group,
`IPR2019-01609, Paper 11 ........................................................................ 97
`Dolby Lab’ys., Inc., v. Intertrust Techs. Corp.,
`IPR2020-01105, Paper 14 (P.T.A.B. Jan. 5, 2021) ............................ 92, 93
`Global Tel*Link Corp. v. HLFIP Holding, Inc.,
`IPR2021-00444, Paper 14 (P.T.A.B. Jul. 22, 2021) ................................. 95
`NetNut Ltd. v. Bright Data Ltd.,
`IPR2021-00465, Paper 11 (P.T.A.B. Aug. 12, 2021) .............................. 98
`Platform Sci., Inc. v. Omnitracs, LLC,
`IPR2020-01518, Paper 14 (Apr. 15, 2021) .............................................. 92
`Samsung Elecs. Am. Inc. v. Snik LLC,
`IPR2020-01428, Paper 10 (P.T.A.B. Mar. 9, 2021) ................................. 96
`Samsung Elecs. Am., Inc. v. Snik LLC,
`IPR2020-01429, Paper 10 (P.T.A.B. Mar. 9, 2021) ................................. 92
`Sand Revolution II, LLC v. Cont’l Intermodal Grp.-Trucking LLC,
`IPR2019-01393, Paper 24 (P.T.A.B. June 16, 2020) ............................... 96
`Toshiba Am. Info. Sys., Inc. v. Walletex Microelecs. Ltd.,
`IPR2018-01538, Paper 11 (P.T.A.B. Mar. 5, 2019) ................................. 98
`
`iv
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`

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`Petition for Inter Partes Review of U.S. Patent No. 8,326,611
`
`Twitter, Inc. v. Palo Alto Rsch. Ctr., Inc.,
`IPR2021-01459, Paper 11 (P.T.A.B. Apr. 6, 2022) ................................. 94
`Uniloc 2017 LLC v. Samsung Elecs. Am., Inc.,
`No. 2:19-cv-00259-JRG-RSP, 2020 WL 1433960
`(E.D. Tex. Mar. 24, 2020) ........................................................................ 95
`Well-man, Inc. v. Eastman Chem. Co.,
`642 F.3d 1355 (Fed. Cir. 2011) ................................................................ 10
`
`Statutes and Rules:
`35 U.S.C. §101 ............................................................................................... 10
`35 U.S.C. §102 ................................................................................................. 6
`35 U.S.C. §103 ................................................................................................. 4
`35 U.S.C. §112 ............................................................................................... 10
`35 U.S.C. §325(d) .......................................................................................... 98
`37 C.F.R. § 42 .........................................................................................passim
`
`Miscellaneous:
`Berglund, B, “Source and effects of low-frequency noise,” 1996 May; J.
`Acoust. Soc. Am; 99(5): 2985-3002 ........................................................ 92
`Byrne, D, “An international comparison of long-term average speech
`spectra,” 1994 Oct; J. Acoust. Soc. Am.; 96(4): 2108-2120 ................... 91
`
`v
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`

`

`Petition for Inter Partes Review of U.S. Patent No. 8,326,611
`
`EXHIBITS
`
`U.S. Patent No. 8,326,611 to Petit et al. (“the ‘611 patent”)
`Excerpts from the Prosecution History of the ‘611 patent (“the
`Prosecution History”)
`Declaration of Dr. Thomas Kenny
`Curriculum Vitae of Dr. Thomas Kenny
`U.S. Patent No. 8,194,880 B2 (“Avendano ’880”)
`U.S. Patent No. 8,204,252 B1 (“Avendano ’252”)
`U.S. App. No. 11/699,732 (“Avendano Priority Application”)
`U.S. Patent No. 7,155,019 B2 (“Hou”)
`
`Ex. 1001
`Ex. 1002
`
`Ex. 1003
`Ex. 1004
`Ex. 1005
`Ex. 1006
`Ex. 1007
`Ex. 1008
`
`Table of Exhibits, Page 1
`
`

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`Petition for Inter Partes Review of U.S. Patent No. 8,326,611
`
`LISTING OF CHALLENGED CLAIMS
`
`A method comprising:
`forming a first virtual microphone;
`forming a filter by generating a first quantity by applying a calibration
`to a second signal of a second physical microphone, generating a
`second quantity by applying the delay to a first signal of a first
`physical microphone, and forming the filter as a ratio of the first
`quantity to the second quantity;
`forming a second virtual microphone by applying the filter to the first
`signal to generate a first intermediate signal, and summing the first
`intermediate signal and the second signal; and
`generating a ratio of energies of the first virtual microphone and the
`second virtual microphone and detecting acoustic voice activity using
`the ratio.
`
`The method of claim 29, wherein the first virtual microphone and the
`second virtual microphone have approximately similar responses to
`noise and approximately dissimilar responses to speech.
`
`The method of claim 29, comprising applying a calibration to at least
`one of the first signal and the second signal, wherein the calibration
`compensates a second response of the second physical microphone so
`that the second response is equivalent to a first response of the first
`physical microphone.
`
`The method of claim 29, comprising applying a delay to the first
`intermediate signal, wherein the delay is proportional to a time
`difference between arrival of the speech at the second physical
`microphone and arrival of the speech at the first physical microphone.
`
`Claim 29
`[29pre]
`[29a]
`[29b]
`
`[29c]
`
`[29d]
`
`Claim 30
`[30]
`
`Claim 31
`[31]
`
`Claim 32
`[32]
`
`Claim 33
`
`1
`
`

`

`Petition for Inter Partes Review of U.S. Patent No. 8,326,611
`
`[33]
`
`The method of claim 29, wherein the forming of the first virtual
`microphone comprises applying the filter to the second signal.
`
`Claim 34
`[34]
`
`Claim 35
`[35]
`
`Claim 36
`[36]
`
`Claim 37
`[37]
`Claim 38
`[38]
`
`Claim 39
`[39]
`
`Claim 40
`[40]
`
`Claim 41
`[41]
`
`Claim 42
`
`The method of claim 33, wherein the forming of the first virtual
`microphone comprises applying the calibration to the second signal.
`
`The method of claim 34, wherein the forming of the first virtual
`microphone comprises applying the delay to the first signal.
`
`The method of claim 35, wherein the forming of the first virtual
`microphone by the combining comprises subtracting the second signal
`from the first signal.
`
`The method of claim 29, wherein the filter is an adaptive filter.
`
`The method of claim 29, comprising adapting the filter to minimize a
`second virtual microphone output when only speech is being received
`by the first physical microphone and the second physical microphone.
`
`The method of claim 37, wherein the adapting comprises applying a
`least-mean squares process.
`
`The method of claim 37, comprising generating coefficients of the
`filter during a period when only speech is being received by the first
`physical microphone and the second physical microphone.
`
`The method of claim 29, wherein the generating of the ratio comprises
`generating the ratio for a frequency band.
`
`2
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`

`

`Petition for Inter Partes Review of U.S. Patent No. 8,326,611
`
`[42
`
`The method of claim 29, wherein the generating of the ratio comprises
`generating the ratio for a frequency subband.
`
`Claim 43
`[43]
`
`Claim 44
`
`[44pre]
`[44a]
`
`[44b]
`
`[44c]
`
`[44d]
`
`
`
`
`The method of claim 29, comprising generating a vector of the ratio
`versus time.
`
`A method comprising:
`forming a first virtual microphone by generating a first combination
`of a first signal and a second signal, wherein the first signal is received
`from a first physical microphone and the second signal is received
`from a second physical microphone;
`forming a filter by generating a first quantity by applying a calibration
`to at least one of the first signal and the second signal, generating a
`second quantity by applying a delay to the first signal, and forming
`the filter as a ratio of the first quantity to the second quantity;
`forming a second virtual microphone by applying the filter to the first
`signal to generate a first intermediate signal and summing the first
`intermediate signal and the second signal; and
`determining a presence of acoustic voice activity of a speaker when
`an energy ratio of energies of the first virtual microphone and the
`second virtual microphone is greater than a threshold value.
`
`
`
`3
`
`

`

`Petition for Inter Partes Review of U.S. Patent No. 8,326,611
`
`Petitioner LG Electronics Inc. (“LGE” or “Petitioner”) petitions for inter
`
`partes review (“IPR”) of claims 29-44 (“Challenged Claims”) of U.S. Patent No.
`
`8,326,611 (“the ’611 patent”).
`
`I.
`
`REQUIREMENTS FOR IPR1
`A. Grounds for Standing
`Petitioner certifies that the ’611 patent is available for IPR. This petition is
`
`being filed within one year of service of the original complaint against Petitioner in
`
`the district court litigation. Petitioner is not barred or estopped from requesting this
`
`review.
`
`B. Challenge and Relief Requested
`Petitioner requests IPR on the following grounds.
`
`Ground
`1
`2
`
`Claims
`29-31, 33-37, 41-44
`32, 38-40
`
`§103 Basis
`Avendano ’880, Hou
`
`Avendano ’880, Avendano ’252,
`Hou
`
`
`
`
`1 Sections I-IV of this petition are substantively identical to the corresponding
`
`sections in Amazon.com, Inc. v. Jawbone Innovations, LLC, IPR2023-00285, Paper
`
`1 (P.T.A.B. Nov. 28, 2022), which Petitioner seeks to join pursuant to the motion
`
`for joinder and consolidation filed herewith.
`
`4
`
`

`

`Petition for Inter Partes Review of U.S. Patent No. 8,326,611
`
`C.
`Priority Date
`The ’611 patent was filed 10/26/2009 as a continuation-in-part of applications
`
`filed 05/25/2007 and 06/13/2008, and claims priority to a provisional application
`
`filed 10/24/2008.
`
`The Challenged Claims are not entitled to the 05/25/2007 and 06/13/2008
`
`dates because neither CIP application discloses: (i) “forming a filter by generating a
`
`first quantity by applying a calibration to a second signal of a second physical
`
`microphone, generating a second quantity by applying the delay to a first signal of a
`
`first physical microphone, and forming the filter as a ratio of the first quantity to the
`
`second quantity” (as recited in independent claim 29), (ii) “forming a filter by
`
`generating a first quantity by applying a calibration to at least one of the first signal
`
`and the second signal, generating a second quantity by applying a delay to the first
`
`signal, and forming the filter as a ratio of the first quantity to the second quantity”
`
`(as recited in independent claim 44), and (iii) “determining a presence of acoustic
`
`voice activity of a speaker when an energy ratio of energies of the first virtual
`
`microphone and the second virtual microphone is greater than a threshold value” (as
`
`recited in independent claim 44). Thus, the earliest possible priority date is
`
`10/24/2008 (“Critical Date”).
`
`Each reference qualifies as prior art:
`
`
`
`5
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`

`Petition for Inter Partes Review of U.S. Patent No. 8,326,611
`
`Reference
`Avendano ’880
`Avendano ’252
`
`Hou
`
`
`
`Date
`01/29/2007 (filed)
`03/31/2008 (filed)
`01/29/2007 (filed, priority
`application)
`03/14/2001 (filed)
`
`Section
`§102(e)
`§102(e)
`
`§102(e)
`
`Avendano ’252 qualifies as prior art because its filing date (03/31/2008) and
`
`the filing date of U.S. App. No. 11/699,732 (“Avendano Priority Application”)
`
`(01/29/2007), from which Avendano ’252 claims priority, predate the Critical Date.2
`
`1.
`Dynamic Drinkware Analysis
`Avendano ’252 claims priority to the Avendano Priority Application. Ex.
`
`1006, 1:8-23. The Avendano Priority Application is incorporated in its entirety in
`
`Avendano ’252. Id. Avendano ’252 is entitled to the 01/29/2007 filing date because
`
`the Avendano Priority Application includes the relevant prior art disclosure and
`
`supports at least one of Avendano ’252’s claims (claim 1), as shown below.
`
`(a) A method for adaptive processing of a close
`microphone array in a noise suppression system,
`comprising:
`Ex. 1007, [0008], [0021], [0062]-[0070], FIGS. 7-8; Ex. 1003, ¶85.
`
`(b)
`
`receiving a primary acoustic signal and a
`secondary acoustic signal;
`
`
`2 The Avendano Priority Application issued as Avendano ’880.
`
`6
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`

`Petition for Inter Partes Review of U.S. Patent No. 8,326,611
`
`Ex. 1007, [0009], [0022]-[0024], [0027], [0029], [0062], FIGS. 1a-1b, 2-5, 7;
`
`Ex. 1003, ¶85.
`
`(c)
`
`performing frequency analysis on the primary
`and secondary acoustic signals to obtain primary
`and secondary sub-band signals;
`Ex. 1007, [0010]-[0011], [0029]-[0037], [0053]-[0060], [0063]-[0064], FIGS.
`
`3-5, 7; Ex. 1003, ¶85.
`
`(d)
`
`generating a forward-facing cardioid pattern
`and a backward-facing cardioid pattern based
`on the sub-band signals;
`Ex. 1007, [0010]-[0011], [0029]-[0037], [0053]-[0061], [0063]-[0064], FIGS.
`
`3-7; Ex. 1003, ¶85.
`
`(e)
`
`generating a forward-facing cardioid pattern
`and a backward-facing cardioid pattern based
`on the sub-band signals;
`Ex. 1007, [0010]-[0011], [0029]-[0037], [0053]-[0061], [0063]-[0064], FIGS.
`
`3-7; Ex. 1003, ¶85.
`
`(f)
`outputting a noise suppressed signal.
`Ex. 1007, [0011], [0038]-[0052], [0065]-[0071], FIGS. 3-5, 7, 8; Ex. 1003,
`
`¶85.
`
`7
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`

`

`Petition for Inter Partes Review of U.S. Patent No. 8,326,611
`
`II. BACKGROUND
`A. The ’611 Patent
`The ’611 patent “relates to noise suppression systems, devices, and methods
`
`for use in acoustic applications.” Ex. 1001, 1:16-18; Ex. 1003, ¶¶42-49. A first
`
`virtual microphone (V1) is generated by (i) applying a delay filter (z-γ) to a signal
`
`from a first physical microphone (O1), (ii) applying a calibration filter (α(z)) and an
`
`adaptive filter (β(z)) to a signal from a second physical microphone (O2), and (iii)
`
`combining the filtered signals. Ex. 1001, 5:20-6:19, FIG. 4.
`
`Ex. 1001, FIG. 43
`A second virtual microphone (V2) is generated by (i) applying an adaptive
`
`filter (β(z)) and a delay filter (z-γ) to the signal from a first physical microphone(O1),
`
`
`3 Red annotations added throughout.
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`8
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`Petition for Inter Partes Review of U.S. Patent No. 8,326,611
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`(ii) applying a calibration filter (α(z)) to the signal from a second physical
`
`microphone (O2), and (iii) combining the filtered signals. Id., 5:20-6:19, FIG. 3.
`
`
`
`Ex. 1001, FIG. 3
`The ratio of energies of the first and second virtual microphones is used “to
`
`determine when speech is occurring.” Id., 6:20-10:8, FIGS. 5-11. A ratio that is
`
`greater than a threshold value is indicative of acoustic voice activity, whereas a ratio
`
`that is less than the threshold value is indicative of an absence of acoustic voice
`
`activity. Id., 6:47-51, 7:5-7, FIGS. 5-11; Ex. 1003, ¶42-49.
`
`B.
`Prosecution History
`The claims were allowed after the filing of a terminal disclaimer over U.S.
`
`App. No. 12/606,146. Ex. 1002, 195-196, 218-219, 227-233. None of Avendano
`
`’880, the Avendano Priority Application, Hou, or Avendano ’252 was cited during
`
`prosecution of the ’611 patent. Ex. 1003, ¶50.
`
`9
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`

`Petition for Inter Partes Review of U.S. Patent No. 8,326,611
`
`C. Level of Ordinary Skill
`A person of ordinary skill in the art (“POSITA”) would have at least a
`
`bachelor of science in electrical engineering, computer engineering, computer
`
`science, mechanical engineering, or a related discipline, with at least two years of
`
`relevant experience in a field related to acoustics, speech recognition, speech
`
`detection, or signal processing. Ex. 1003, ¶¶22-23. Additional education or industry
`
`experience may compensate for a deficit in the other. Id.
`
`D. Claim Construction
`No formal claim constructions are necessary because “claim terms need only
`
`be construed to the extent necessary to resolve the controversy.” Well-man, Inc. v.
`
`Eastman Chem. Co., 642 F.3d 1355, 1361 (Fed. Cir. 2011).4
`
`III. GROUND 1: Avendano ’880 and Hou (Claims 29-31, 33-37, 41-44)
`A. Avendano ’880 Overview
`Avendano ’880 determines “inter-microphone level differences (ILD) ...based
`
`on energy level differences of a pair of omni-directional microphones,” and uses
`
`ILD “to attenuate noise and enhance speech.” Ex. 1005, 2:5-9; Ex. 1003, ¶¶51-67.
`
`
`4 Petitioner neither concedes that each claim satisfies all statutory requirements,
`
`such as §§101 and 112, nor waives any arguments concerning claim scope or
`
`grounds that cannot be raised here.
`
`10
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`Petition for Inter Partes Review of U.S. Patent No. 8,326,611
`
`Avendano ’880 discloses “audio device 104” having “primary microphone
`
`106” and “secondary microphone 108,” which may be “omni-directional
`
`microphone[s].” Ex. 1005, 3:27-35; FIGS. 1a-1b; Ex. 1003, ¶52.
`
`Ex. 1005, FIG. 1a
`
`
`
`
`
`Ex. 1005, FIG. 1b
`Avendano ’880’s “primary microphone 106 is much closer to [an] audio
`
`source 102 than the secondary microphone 108,” and thus “the intensity level is
`
`higher for the primary microphone 106 resulting in a larger energy level during a
`
`speech/voice segment.” Ex. 1005, 3:45-55, FIGS. 1a-1b; Ex. 1003, ¶53.
`
`11
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`

`Petition for Inter Partes Review of U.S. Patent No. 8,326,611
`
`Avendano ’880 uses this “level difference … to discriminate speech and noise
`
`in the time-frequency domain.” Ex. 1005, 3:55-57; Ex. 1003, ¶¶54-55. For example,
`
`Avendano ’880 receives signals from the two microphones (signals x1 and x2), and
`
`processes the signals using “differential microphone array (DMA) module 302” to
`
`“create two different directional patterns around the audio device 104.” Ex. 1005,
`
`4:20-41. As Avendano ’880 explains, “[e]ach directional pattern is a region about
`
`the audio device 104 in which sounds generated by an audio source 102 within the
`
`region may be received by the microphones 106 and 108 with little attenuation,” and
`
`“[s]ounds generated by audio sources 102 outside of the directional pattern may be
`
`attenuated.” Id., 4:41-46.
`
`Avendano ’880’s DMA module 302 generates (i) a first processed signal having a
`
`directional pattern for receiving sounds “within a front cardioid region around the
`
`audio device 104” (i.e., “cardioid primary signal (Cf)”), and (ii) a second processed
`
`signal having a directional pattern for receiving sounds “within a back cardioid
`
`region around the audio device 104” (i.e., “cardioid secondary signal (Cb)”). Id.,
`
`4:47-52, 5:25-35, 9:29-42, FIG. 6 (below); Ex. 1003, ¶¶56-59.
`
`12
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`

`

`Petition for Inter Partes Review of U.S. Patent No. 8,326,611
`
`
`
`
`Ex. 1005, FIG. 6
`Avendano ’880’s “cardioid primary signal (Cf)” is generated by combining (i)
`
`signal x1 from primary microphone 106, and (ii) signal x2 from secondary
`
`microphone 108 (signal x2 having been delayed by “delay node 404” and filtered by
`
`“gain module 406”). Ex. 1005, 5:15-35, FIG. 4a; Ex. 1003, ¶60. Avendano ’880’s
`
`“cardioid secondary signal (Cb)” is generated by combining (i) signal x2 from
`
`secondary microphone 108, and (ii) signal x1 from primary microphone 106 (signal
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`x1 having been delayed by “delay node 402”). Ex. 1005, 5:15-35, FIG. 4a; Ex. 1003,
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`¶60. The “delay nodes” are implemented using filters (“allpass filters”). Ex. 1005,
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`8:47-51; Ex. 1003, ¶60.
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`
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`Ex. 1005, FIG. 4a
`Further, Avendano ’880 detects speech based on the ratio between (i) the
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`energy of “cardioid primary signal (Cf)” and (ii) the energy of “cardioid secondary
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`signal (Cb).” Id., 5:49-6:34; Ex. 1003, ¶¶61-66. Specifically, an “energy level” (Ef)
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`associated with “cardioid primary signal (Cf)” is calculated:
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`Ex. 1005, 5:60
`Further, an “energy level” (Eb) associated with “cardioid secondary signal
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`(Cb)” is calculated:
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`Ex. 1005, 6:5
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`The ratio between these two energy levels (ILD) is determined:
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`
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`Ex. 1005, 6:16
`Avendano ’880 compares the ratio (ILD) to a “threshold” to determine the
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`presence or absence of speech:
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`
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`PPLE-1005, 6:61
`If the ratio (ILD) is “smaller than a threshold value (e.g., threshold=0.5) above
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`which speech is expected to be,” a value λ1 is set to zero (e.g., indicating an absence
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`of speech). Ex. 1005, 6:58-7:3. However, if the ratio (ILD) “starts to rise (e.g.,
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`because speech is present within the large ILD region), λ1 increases” (e.g., is set to
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`one, indicating a presence of speech). Id.
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`Avendano ’880’s ratio is used to process audio signals “through a noise
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`reduction system 310” to “enhance the speech of the primary acoustic signal.” Id.,
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`Abstract, 6:35-8:23, 10:18-50, FIGS. 7-8; Ex. 1003, ¶67.
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`B. Hou Overview
`Hou describes “[i]mproved approaches
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`to matching sensitivities of
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`microphones in multi-microphone directional processing systems ... so that
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`directional noise suppression is robust.” Ex. 1008, Abstract; Ex. 1003, ¶¶68-78.
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`Specifically, Hou’s “two-microphone directional processing system 500”
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`“compensate[s] (or correct[s]) for the relative difference in sensitivity between ...
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`mismatched first and second microphones” and produces an “output signal ...
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`hav[ing] robust directionality despite a mismatch between the first and second
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`microphones.” Ex. 1008, 5:25-56, FIG. 5.
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`As Hou explains, a system generates directional signals by suppressing sounds
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`(e.g., “interference”) coming from particular directions relative to a system. Id.,
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`1:22-2:2; Ex. 1003, ¶70. In particular, an “output signal” that is directional “is
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`dependent on which directions the input signals come from.” Ex. 1008, 1:22-2:2.
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`Further, “[t]he sensitivity of the microphones of the sound pick up system must be
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`matched in order to achieve good directionality.” Id.
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`Hou describes various techniques for producing directional signals. Ex. 1003,
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`¶¶71-77. In one example, Hou’s system receives “a first electronic sound signal”
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`from “microphone 502,” and “estimates the minimum for the first electronic sound
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`signal” using “first minimum estimate unit 508” (e.g., by measuring the minimum
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`for the first electronic sound signal “over a time constant duration”). Ex. 1008, 5:27-
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`41, FIG. 5.
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`Further, Hou’s system receives “a second electronic sound signal” from
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`“microphone 504,” delays the “second electronic sound signal” using “delay unit
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`506,” and “estimates the minimum for the second electronic sound signal” using
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`“second minimum estimate unit 510” (e.g., by measuring the minimum for the
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`second electronic sound signal “over a time constant duration”). Id.
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`Further, “divide unit 512 produces a quotient by dividing the first minimum
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`estimate by the second minimum estimate,” where “[t]he quotient represents a
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`scaling amount that is sent to a multiplication unit 514.” Id., 5:42-45.
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`Further, “[t]he second electronic sound signal is then multiplied with the
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`scaling amount to produce a compensated sound signal.” Id., 5:45-47. “The
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`compensated sound signal is thus compensated (or corrected) for the relative
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`difference in sensitivity between the mismatched first and second microphones 502
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`and 504.” Id., 5:47-50.
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`
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`Ex. 1008, FIG. 5
`Further, “subtraction unit 516 then subtracts the compensated electronic
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`sound signal from the first electronic sound signal to produce an output signal ...
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`hav[ing] robust directionality despite a mismatch between the first and second
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`microphones 502 and 504.” Id., 5:50-56.
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`As Hou describes, generating a compensated sound signal ensures that
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`“directional noise suppression is not affected by microphone mismatch, ... the drift
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`of microphone sensitivity over time, ... [or] the non-uniform distribution of sound
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`pressure in real-life application.” Id., 9:28-41; Ex. 1003, ¶78.
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`C. Combination of Avendano ’880 and Hou
`A POSITA would have found it obvious to combine Avendano ’880 with Hou.
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`Ex. 1003, ¶¶86-126.
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`Motivations for Combining Avendano ’880 and Hou
`A POSITA would have been motivated to combine Avendano ’880 with Hou
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`for several reasons. Ex. 1003, ¶¶87-100.
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`First, both Avendano ’880 and Hou come from the same field of endeavor of
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`enhancing speech and attenuating noise. Ex. 1005, Abstract, 1:24-26, 3:13-26, 3:42-
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`60; Ex. 1008, Abstract, 2:44-52, 4:40-49; Ex. 1003, ¶88.
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`Second, both Avendano ’880 and Hou describe enhancing speech and
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`attenuating noise using similar techniques, including (i) capturing signals from at
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`least two physical microphones, and (ii) processing these signals in various ways,
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`including equalizing the signal levels of two signals and generating directional
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`signals based on the equalized signals. Ex. 1003, ¶¶89-94.
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`For example, Avendano ’880’s “primary microphone 106 is much closer to
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`[an] audio source 102 than the secondary microphone 108,” and thus “the intensity
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`level is higher for the primary microphone 106 resulting in a larger energy level
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`during a speech/voice segment.” Ex. 1005, 3:27-55; Section III(A); Ex. 1003, ¶90.
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`To account for the differences in intensity levels, Avendano ’880’s “DMA module
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`302” applies “gain factor, g” to a second signal “to equalize the signal levels” of the
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`first and second signals. Ex. 1005, 5:36-39, 9:54-59, FIGS. 4a-4b; Ex. 1003, ¶91.
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`Such equalization is beneficial, as “systems can suffer loss of performance when the
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`microphone signals have different levels.” Ex. 1005, 5:37-39; Ex. 1003, ¶91.
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`Further, Avendano ’880’s “DMA module 302” uses the equalized signal to generate
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`directional signals, such as “cardioid primary signal (Cf)” (front) and “cardioid
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`secondary signal (Cb)” (back). Ex. 1005, 4:41-52, 5:25-35, FIGS. 4a-4b, 6; Ex. 1003,
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`¶92.
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`Hou’s “system 500” serves a similar function as Avendano ’880’s “DMA
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`module 302,” namely “compensat[ing] (or correct[ing]) for the relative difference in
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`sensitivity between ... mismatched first and second microphones.” Ex. 1008, 5:47-
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`50; Ex. 1003, ¶¶93-94. Similarly, Hou explains that compensation or correction is
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`beneficial, as “[t]he sensitivity of the microphones of the sound pick up system must
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`be matched in order to achieve good directionality.” Ex. 1008, 1:48-2:2; Ex. 1003,
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`¶93. Further, like Avendano ’880, Hou processes the compensated or corrected
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`signal to generate a directional signal (e.g., “an output signal ... ha