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`UNITED STATES PATENT AND TRADEMARK OFFICE
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`____________________
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`BEFORE THE PATENT TRIAL AND APPEAL BOARD
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`____________________
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`APPLE INC.
`Petitioner,
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`v.
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`ANDREA ELECTRONICS INC.,
`Patent Owner.
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`Patent No. 6,363,345
`____________________
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`Inter Partes Review No. IPR2017-00626
`__________________________________________________________________
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`Petitioner’s Reply
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`Table of Contents
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`2.
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`Introduction .................................................................................................... 1
`I.
`II. Claim Construction ....................................................................................... 2
`III. Hirsch Anticipates Claims 1-3, 12-13, 21, 23, and 38 ................................. 2
`IV. Hirsch and Martin Render Claims 4-11, 25, 39-42, and 46 Obvious ........ 3
`A. Martin Discloses the “Future Minimum” of Claims 4 and 39 ........ 3
`1.
`Andrea’s Argument Does Not Apply Where the Martin
`Algorithm Is Configured to Use 1 Sub-Window ........................ 5
`Andrea’s Argument Depends on the Non-Existent Claim
`Requirement that a “Future Minimum” Be a Minimum “Across
`the Entire Window L” ................................................................. 8
`B. Martin Discloses Setting a Current Minimum to a Future
`Minimum Value “Periodically,” as Required by Claim 6 ............. 11
`C. Martin Discloses the “Current Minimum Value” of Claim 10 ..... 13
`D. A Skilled Artisan Would Have Combined Hirsch and Martin ..... 16
`E.
`Andrea’s Criticisms of Dr. Hochwald Are Unfounded ................. 21
`V. A POSA Would Have Considered it Obvious to Modify Hirsch and
`Martin with Conventional Spectral Subtraction Techniques ................. 22
`A. A POSA Would Have Combined Hirsch with Martin and Boll ... 23
`B.
`A POSA Would Have Combined Hirsch with Boll and Arslan .... 24
`C. A POSA Would Have Combined Hirsch with Martin and
`Uesugi.................................................................................................. 25
`VI. Conclusion .................................................................................................... 26
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`TABLE OF AUTHORITIES
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`Cases
`KSR Intern. Co. v. Teleflex Inc.,
`127 S.Ct. 1727 (2007) ....................................................................... 19, 21, 24, 25
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`Page(s)
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`Exhibit List
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`Reference Name
`U.S. Patent No. 6,363,345
`U.S. Patent No. 6,363,345 File History
`Declaration of Bertrand Hochwald
`[Reserved]
`H. G. Hirsch and C. Ehricher, “Noise estimation techniques for
`robust speech recognition,” Proc. IEEE Int. Conf. Acoustics,
`Speech, Signal Processing, vol. 1, pp. 153 -156, 1995
`(“Hirsch”)
`Rainer Martin, “An Efficient Algorithm to Estimate the
`Instantaneous SNR of Speech Signals,” Proc. Eurospeech, pp.
`1093-96, 1993 (“Martin”)
`Letter from Technische Informationsbibliothek re: Proc.
`Eurospeech 1993 (2 Jan. 2017)
`Proc. Eurospeech 1993 Vol. 2 Table of Contents from
`Technische Informationsbibliothek
`Steven F. Boll, “Suppression of Acoustic Noise in Speech
`Using Spectral Subtraction,” IEEE Transactions on Acoustics,
`Speech, and Signal Processing, Vol. ASSP-27, No. 2, April
`1979 (“Boll”)
`U.S. Patent No. 5,550,924 to Helf (“Helf”)
`U.S. Patent No. 5,706,395 to Arslan (“Arslan”)
`Excerpts from Deller et al., Discrete-Time Processing of Speech
`Signals (1993)
`Excerpt from Merriam-Webster Dictionary (1993)
`Excerpts from Oppenheim and Willsky, Signals and Systems
`(1997)
`U.S. Patent No. 5,459,683 to Uesugi
`Lim and Oppenheim, “Enhancement and Bandwidth
`Compression of Noisy Speech,” Proceedings of the IEEE, vol.
`67, no. 12, pp. 1586-1604, December 1979
`Affidavit of Service in Andrea Elecs. v. Apple Inc., EDNY
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`Exhibit #
`1001
`1002
`1003
`1004
`1005
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`1006
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`1007
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`1008
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`1009
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`1010
`1011
`1012
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`1013
`1014
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`1015
`1016
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`1017
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`1019
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`1020
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`1021
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`1022
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`Exhibit #
`1018
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`Reference Name
`In the Matter of Certain Audio Processing Hardware and
`Software and Products Containing the Same, Inv. No. 337-TA-
`949, Claim Construction Order (U.S.I.T.C. Jan. 27, 2016) (“949
`CC Order”)
`In the Matter of Certain Audio Processing Hardware and
`Software and Products Containing Same, Inv. No. 337-TA-949,
`Complainant Andrea Electronics Corp.’s Initial Claim
`Construction Brief (U.S.I.T.C. Oct. 19, 2015) (“Andrea CC
`Br.”)
`In the Matter of Certain Audio Processing Hardware and
`Software and Products Containing Same, Inv. No. 337-TA-949,
`Commission Investigative Staff’s Initial Markman Brief
`(U.S.I.T.C. Oct. 19, 2015) (“OUII CC Br.”)
`Letter from the parties in 337-TA-949 informing ALJ they
`agreed to certain constructions (Nov. 10, 2015) (prior litigation)
`In the Matter of Certain Audio Processing Hardware, Software,
`and Products Containing The Same, Inv. No. 337-TA-1026,
`Verified Complaint Against Apple Inc. and Samsung Inc.
`Under Section 337 of the Tariff Act of 1930, as Amended
`(U.S.I.T.C. Sept. 19, 2016)
`[NEW] 1023 Hochwald Reply Decl.
`[NEW] 1024 Reserved
`[NEW] 1025 Exhibit 2 from Hochwald Deposition
`[NEW] 1026 Transcript from Deposition of Scott Douglas dated Jan. 17,
`2018
`[NEW] 1027 Exhibit 1 from Douglas Dep., Figure 27 depicting Current and
`Future Minima
`[NEW] 1028 Exhibit 2 from Douglas Dep., Dr. Douglas’s mark up of Exhibit
`1
`[NEW] 1029 Exhibit 8 from Douglas Dep., Declaration of Scott Douglas in
`Support of Complainant Andrea’s Claim Construction Brief in
`Inv. No. 337-TA-949 (Oct. 19, 2015)
`[NEW] 1030 Transcript from Deposition of Scott Douglas dated June 16,
`2017, taken in Inv. No. 337-TA-1026
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`Reference Name
`Exhibit #
`[NEW] 1031 Rainer Martin, Spectral Subtraction Based on Minimum
`Statistics, Proc. EUSIPCO-94, pp. 1182-85 (1994) (“Martin
`94”)
`[NEW] 1032 H. G. Hirsch, “Estimation of Noise Spectrum and its
`Application to SNR Estimation and Speech Enhancement,”
`Technical Report TR-93-012, International Computer Science
`Institute (1993) (reference [7] in Martin 93)
`[NEW] 1033 D. Van Campernolle, “Noise Adaptation in a Hidden Markov
`Model Speech Recognition System”, Computer Speech and
`Language, Vol. 3, pp. 151-167 (1989) (reference [3] in Martin
`93)
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`I.
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`Introduction
`Patent Owner Andrea raises no challenge to the Board’s initial finding that
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`Hirsch anticipates claims 1-3, 12-13, 21, 23, and 38, effectively conceding that
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`these claims are unpatentable. See Paper 11 (“Resp.”), 12. Andrea instead devotes
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`the bulk of its Response to arguing that dependent claims 4-11 and 39-41—which
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`cover a process for tracking the noise floor of an audio signal—are patentable over
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`the combination of Hirsch and Martin. See Resp., 25 (admitting that “claim 4
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`recites the ‘future minimum’ as a noise floor tracker” (emphasis added)).
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`But Martin teaches the same noise floor tracking algorithm used in the
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`claims and disclosed in the patent. As Martin states, “[t]o estimate the noise floor
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`our algorithm takes the minimum of a [signal] within a window of finite length.”
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`Ex. 1006(Martin), 1093 (emphasis added). Hirsch and Martin thus together teach
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`every element of these claims. Unable to seriously dispute that Martin teaches use
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`of a noise floor tracking algorithm, Andrea next argues that Martin calculates the
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`noise floor over the wrong data window. Resp., 25. But the claims, by their
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`explicit terms, do not impose the restraints that Andrea contends differentiates
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`them from Martin: the ’345 claims do not specify the use of a data “window” nor
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`do they limit the period over which the noise floor is tracked.
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`Andrea also asserts a person of ordinary skill in the art (“POSA”) would not
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`have even considered Hirsch and Martin together. But Andrea’s position lacks
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`merit as it rests on non-existent differences between the references. More than a
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`preponderance of the evidence shows that Hirsch and Martin render these claims
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`obvious.
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`Andrea does not dispute that the other challenged claims (which all depend
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`from either claim 1 or 38) simply recite conventional features of the spectral
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`subtraction process or that Hirsch and the secondary references disclose these
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`features. Instead, Andrea contends only that a POSA would not have been
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`motivated to modify Hirsch to incorporate these known features. But, as explained
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`the Petition, a POSA would have had ample reason to modify Hirsch to use these
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`conventional features to solve standard problems present in any spectral
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`subtraction system. Accordingly, the Board should cancel claims 1-25 and 38-47.
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`II. Claim Construction
`The Board need not construe any claims because under any reasonable
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`construction, Hirsch alone or in combination Martin and/or other references
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`renders the claims obvious.
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`III. Hirsch Anticipates Claims 1-3, 12-13, 21, 23, and 38
`Andrea does not dispute that claims 1-3, 12-13, 21, 23, and 381 are
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`anticipated by Hirsch. Resp., 12 (“Patent Owner does not address the anticipation
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`1 All challenged claims depend from independent claims 1 and 38.
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`grounds with respect to the Hirsch reference.”). The Board should therefore cancel
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`these claims for the reasons stated in the Petition and Institution Decision.
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`IV. Hirsch and Martin Render Claims 4-11, 25, 39-42, and 46 Obvious
`Andrea’s primary challenge to these claims is that Martin does not teach the
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`“future minimum” element of claims 4 and 39, from which claims 5-11 and 40-42
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`depend, respectively. Andrea also argues that Martin does not teach elements of
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`claims 6 and 10, and that a POSA would not have combined Hirsch with Martin.2
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`Andrea’s arguments lack merit.
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`A. Martin Discloses the “Future Minimum” of Claims 4 and 393
`The Board correctly found that the combination of Hirsch and Martin
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`renders claims 4 and 39 obvious. Claim 4 depends from claim 1 and specifies
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`“set[ting] the threshold… in accordance with a current minimum value… of the
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`corresponding frequency bin; said current minimum value being derived in
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`accordance with a future minimum value… of the corresponding frequency bin.”
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`Claim 39 depends from claim 38 and specifies the same limitation.
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`2 Because Andrea does not separately address claims 5, 7-9, 11, 25, 40-42, or 46,
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`Apple does not either.
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`3 In a heading, Andrea states that Martin does not disclose the “current minimum,”
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`but it does not substantively analyze that term.
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`In the Petition, Apple explained how Martin’s algorithm mapped to the
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`elements of claim 4. Martin teaches a noise estimation algorithm that tracks the
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`noise floor of an audio signal over windows of L digital samples, and each window
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`can correspond to a period of, e.g., 0.625 seconds. Pet., 33, 40; Ex. 1003, ¶¶135-
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`39. Martin shows that the window L can be divided into an arbitrary number of
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`sub-windows W, each of length M samples (where L=MxW). Ex. 1003, ¶¶135,
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`139. Martin uses an example that has 4 sub-windows (W=4), but teaches that any
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`number of sub-windows can be used. Id.
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`During each sub-window, Martin uses the variable PMmin (“future minimum”)
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`to track the signal’s minimum value. Pet., 38-39, 42. At the end of a sub-window,
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`PMmin is used to update the noise floor Pn(i) (“current minimum”) by either (1)
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`setting Pn(i) equal to the PMmin observed in that sub-window or (2) setting Pn(i)
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`equal to the smallest PMmin observed over the past L samples (which corresponds to
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`W sub-windows). Ex. 1003, ¶¶135-36. Where the PMmin value over the past W sub-
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`windows is monotonically increasing (meaning that each is higher than the
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`previous one), update option (1) is used, otherwise option (2) is used. Ex.
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`1006(Martin), 1094. Martin also teaches a process for immediately updating the
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`noise floor before a sub-window is over. Pet., 45. If the current value of the signal
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`((cid:1842)(cid:3364)x) ever drops below the noise floor Pn(i), the noise floor is immediately updated
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`to be equal to the signal’s current value. Ex. 1003, ¶142.
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`In Response, Andrea asserts that Martin does not teach a “future minimum
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`value,” alleging that PMmin “is not the minimum magnitude of a frequency bin”
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`because it is the minimum of a sub-window of length M in Martin and not of a
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`window of length L. Resp., 25-27. Andrea’s argument should be rejected because
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`it both mischaracterizes Martin and reads non-existent limitations into the claims.
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`1.
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`Andrea’s Argument Does Not Apply Where the Martin
`Algorithm Is Configured to Use 1 Sub-Window
`Where Martin is configured to use 1 sub-window (W=1), the sub-window
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`(M) and window (L) are the same length, and thus the minimum of the sub-window
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`is also the minimum of the window. Ex. 1003, ¶139; Ex. 1023, ¶¶5, 11. In this
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`configuration, any purported distinction between windows and sub-windows in
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`Martin vanishes and Andrea’s argument is irrelevant.
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`In an attempt to distinguish Martin, Andrea asserts that Martin does not
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`disclose using a single sub-window. See Resp., 21-22. But as Dr. Hochwald
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`previously explained, Martin discloses that the number of sub-windows in his
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`algorithm is a variable W and teaches that the number of sub-windows can be
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`changed and adapted to a desired configuration. Ex. 1003, ¶139; Ex. 2005, 77:3-
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`22; see Ex. 1006(Martin), 1094. Dr. Hochwald explains that Martin describes the
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`operation of his algorithm using equations that use the variables M, L, and W, and
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`that the equations all work for any positive value of W. Ex. 1023, ¶¶5-7, 9-10; see
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`Ex. 1003, ¶139. A POSA reading Martin would understand that Martin discloses
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`setting the number of sub-windows W to 1. Ex. 1003, ¶¶135, 139; Ex. 2005, 77:3-
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`22, 88:10-22; Ex. 1023, ¶¶4-5.
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`To contest Martin’s explicit disclosure, Andrea alleges that a POSA would
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`not be able to make Martin’s algorithm work where W=1 because that person
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`would not know which of Martin’s two noise update equations (the monotonically
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`increasing option or non-monotonically increasing option) to use to update the
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`noise floor. Resp., 18. But as Dr. Hochwald explains, where W=1 both update
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`equations are identical, and thus, the choice is irrelevant. Ex. 1023, ¶¶11-12; see
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`Ex. 2005, 82:1-85:1. As shown in the annotated excerpt below, the noise floor
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`update equations (blue box) are defined using the variables W and M.
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`Ex. 1023, ¶20; Ex. 1003, ¶140. As shown on the right, when power is
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`monotonically increasing Pn(i)=PMmin. When power is not monotonically
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`increasing, Pn(i) is set equal to the minimum of the past W PMmin values that are
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`stored in min_vec. As Dr. Hochwald explains, after plugging in W=1 to the
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`equation, the non-monotonically increasing update simplifies to Pn(i)=PMmin. Ex.
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`1023, ¶¶11-12. Therefore, when W=1, Pn(i) is set to the same PMmin value
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`irrespective of which update equation is used. See Ex. 2005, 82:1-85:1.
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`Implicitly recognizing that Martin’s algorithm works with 1 sub-window,
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`Andrea incorrectly argues that the use of sub-windows is central to Martin’s
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`algorithm. Resp., 21-22, 44-45. But Martin explains that the central concept of its
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`algorithm is using minimum values to track a noise floor of an audio signal. Ex.
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`1006(Martin), 1093 (“The algorithm is based on the observation that a noise power
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`estimate can be obtained using minimum values of a smoothed power estimate”),
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`1093 (“[t]o estimate the noise floor our algorithm takes the minimum of a
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`smoothed power estimate within a window of finite length.”). In contrast to the
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`central concept of using minimum values to track a noise floor, Martin describes
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`sub-windows as an optional feature that can reduce “computational complexity
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`and delay.” Ex. 1006(Martin), 1094; Ex. 1023, ¶7. While Martin states that the
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`window length L “must be large enough to bridge any peak of speech activity, but
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`short enough to follow nonstationary noise variations,” he says nothing about how
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`long a sub-window must be. Ex. 1006(Martin), 1094. Nothing in Martin suggests
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`that the use of sub-windows is required. Ex. 1023, ¶¶6-8.
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`As further evidence of this fact, Prof. Martin wrote a follow-up article
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`(“Martin 94”) that uses the same noise floor algorithm but does not distinguish
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`between the monotonically and non-monotonically increasing power cases. Ex.
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`1023, ¶13 (explaining that Martin 94 does not include a “monotonic decision
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`block”); see Ex. 1031(Martin94), 1183. As Dr. Hochwald explains, if the
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`“monotonic decision block” were of central importance to Martin’s algorithm, the
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`Martin 94 paper describing the same algorithm would presumably at least mention
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`it. Ex. 1023, ¶13. Instead, Martin 94 does not mention the “monotonic decision
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`block,” which confirms that a POSA would have considered the block to be an
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`optional feature of the algorithm. Id.
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`2.
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`Andrea’s Argument Depends on the Non-Existent Claim
`Requirement that a “Future Minimum” Be a Minimum
`“Across the Entire Window L”
`Even where Martin’s algorithm is configured to use multiple sub-windows,
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`it still teaches the claimed “future minimum.” To argue otherwise, Andrea reads
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`non-existent limitations into the claims to require the “future minimum” to be
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`calculated over a particular period of time. Resp., 25-27.
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`Andrea argues that when a signal is monotonically increasing, Martin fails to
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`disclose a “future minimum” because Martin’s variable PMmin tracks the minimum
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`of the sub-window of length M and “is not the minimum across the window L.”
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`Resp., 26 (emphasis added); see id., 25 (“Thus, PMmin is not the minimum of the
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`samples in the window L… Martin intentionally does not use the minimum power
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`value across the entire window L”). Thus, Andrea asserts that when Martin sets
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`the noise floor Pn(i) equal to the most recent PMmin value, the noise floor is set to
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`the minimum of the sub-window M but not the minimum of the window L. Id., 25-
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`26.
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`Andrea’s argument rests on a limitation found nowhere in the claims.
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`Nothing in claims 4 or 39 specifies the period over which the “future minimum”
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`must be calculated. Claims 5 and 40 are the only claims that specify anything
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`about the period over which the “future minimum” must be calculated, and they
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`specify simply that the “future minimum” is calculated “over a predetermined
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`period of time”; they are silent as to how long that period must be. Andrea admits
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`that Martin shows that PMmin tracks the minimum value during the period M,
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`(Resp., 24 (“In the monotonically increasing case, PMmin will always represent the
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`most recent subwindow minimum…”)), and that admission is fatal to Andrea’s
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`argument. Nothing in claims 4 and 39 (or any other claim) requires use of a
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`predetermined period of length L, or prohibits tracking the minimum of a sub-
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`window. Thus, in the scenario where a signal is not monotonically increasing,
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`Martin satisfies the claims. Ex. 1023, ¶18.
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`In the scenario where a signal is not monotonically increasing, Andrea
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`argues that PMmin is not the “future minimum” because Martin sets the noise floor
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`Pn(i) equal to the smallest PMmin value from the past W sub-windows, which is not
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`necessarily the minimum value of the most recent sub-window. Resp., 26-27.
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`Again, Andrea is reading limitations into the claims. Nothing requires calculating
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`the “future minimum” over a particular data window. Nor do the claims prohibit
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`segmenting a data window into sub-windows and using the minimum of a previous
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`sub-window as the “future minimum”.
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`Andrea also tries to manufacture a difference between Martin and the claims
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`by arguing that Martin’s use of the variable “min_vec” to temporarily store the
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`PMmin values means that the noise floor Pn(i) is never set equal to PMmin because it is
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`set to min_vec instead. Resp., 27. But Andrea ignores that min_vec stores the
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`PMmin values and that Martin uses min_vec to determine which PMmin value in the
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`data window L is the smallest. Ex. 1006(Martin), 1094 (showing
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`“min_vec(r*M)=PMmin”); Ex. 1023, ¶¶14-16, 19. The result is that Martin sets the
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`noise floor Pn(i) equal to the smallest PMmin value from min_vec.4 That the smallest
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`PMmin is temporarily stored in min_vec does not change the fact that the noise floor
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`Pn(i) is set to it. Ex. 1023, ¶¶14-16, 19.
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`4 For example, if W=4, Martin will set Pn(i) equal to the smallest of the past 4 PMmin
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`values stored in min_vec.
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`The distinction Andrea attempts to draw between the “collection of
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`min_vec” values and PMmin is illusory. As Dr. Douglas has admitted, the min_vec
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`variable stores the PMmin values, and Martin sets the noise floor Pn(i) equal to the
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`smallest PMmin value in the data window.
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`Q And the min vec values are the PMmin values, correct?
`A They are the PMmin values.
`Q So this assignment in Figure 2 of Martin assigns Pn(i) to the
`smallest PMmin in the data window, correct?
`A Yes.
`Q If the data window was segmented into four subwindows, that
`would be the smallest of four PMmin values, correct?
`A That is correct.
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`Ex. 1030, 177:5-16; Ex. 1026, 87:15-20, 103:7-104:12 (providing similar
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`testimony).
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`B. Martin Discloses Setting a Current Minimum to a Future
`Minimum Value “Periodically,” as Required by Claim 6
`With respect to claim 6, Andrea argues that Martin does not teach updating
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`the current minimum “periodically” by incorrectly stating that Martin sets Pn(i)
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`(“current minimum”) equal to PMmin (“future minimum”) only “sporadically.” See
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`Resp., 28. According to Andrea, Martin sets Pn(i) to PMmin only in the
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`monotonically increasing scenario, and thus, because the signal sometimes
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`monotonically increases and sometimes does not, this assignment occurs randomly
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`not periodically. Id.
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`First, as with claim 4, Andrea’s argument is irrelevant to the scenario where
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`Martin is configured to use 1 sub-window (W=1), and it can be rejected for that
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`reason alone. Second, even where Martin is configured to use multiple sub-
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`windows (e.g., W=4), Andrea’s argument must be rejected because it rests on
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`Andrea’s flawed position that, in the non-monotonically increasing case, Martin’s
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`use of min_vec to determine the smallest PMmin values in a data window means that
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`the noise floor Pn(i) is not set equal to a PMmin value. As explained above, Andrea’s
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`distinction between min_vec and PMmin is illusory, as Dr. Douglas admitted. See
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`§IV.A.2, above; Ex. 1030, 177:5-16 (“Q So this assignment in Figure 2 of Martin
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`assigns Pn(i) to the smallest PMmin in the data window, correct? A Yes.”); Ex.
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`1026, 87:15-20, 103:7-104:12.
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`Martin updates the value Pn(i) after every M samples, as Dr. Douglas
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`admitted. Ex. 1026, 77:16-80:19. Thus, irrespective of whether the signal is
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`monotonically increasing or not, Pn(i) is set equal to PMmin at the end of every sub-
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`window of M samples, as shown in the blue box of the figure below.5 Ex. 1023,
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`¶20.
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`5 Because Martin sets Pn(i) equal to PMmin every M samples, it does so “at regular
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`intervals of time.” Thus, the Board need not construe “periodically,” because
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`Martin teaches it even under Andrea’s narrow proposed construction.
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`C. Martin Discloses the “Current Minimum Value” of Claim 10
`Claim 10 depends from claim 4 and specifies that the “current minimum” is
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`determined as “the minimum value of the magnitude” of the frequency bin “within
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`a predetermined period of time.” Andrea argues Martin does not teach this
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`limitation by mischaracterizing both the claim language and Apple’s position.
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`First, Andrea erroneously asserts that claims 4 and 10 each recite setting the
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`“current minimum” to a distinct minimum value. Resp., 32-33. But no such
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`limitations appear in the claims. Claim 4 specifies “deriving” the “current
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`minimum” in accordance with a “future minimum value of the magnitude of the
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`corresponding frequency bin.” Claim 10 then specifies that the “current minimum
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`value is determined as the minimum value of the magnitude of the corresponding
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`frequency bin within a predetermined period of time.” Thus, claim 10 simply
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`requires the “current minimum” of claim 4 to be determined over a “predetermined
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`period of time.” If the “current minimum” is set equal to the “future minimum”,
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`and the “future minimum” is determined as the minimum value of the signal within
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`a predetermined time period, then the “current minimum” necessarily is as well.
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`Nothing in claim 10 requires setting the “current minimum” to be a different value
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`than the “future minimum” as Andrea contends, and even Dr. Douglas has admitted
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`that they can be set to the same value. Ex. 1026, 47:13-15, 50:13-16.
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`Next, relying on its misinterpretation of the claims, Andrea asserts that
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`Apple “relies on the same parameter, Px(i), to satisfy both ‘minimum magnitude’
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`values recited in claims 4 and 10,” which allegedly improperly maps one element
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`in Martin to two different claim limitations. Resp., 31. But Apple does not rely on
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`Px(i) to satisfy claim 4’s “future minimum” nor the requirements of claim 10.
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`Instead, Apple explained that Martin sets Pn(i) (“current minimum”) equal to PMmin
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`(“future minimum”), and this meets claim 4’s requirement of “deriving” a “current
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`minimum” in accordance with a “future minimum.” Pet., 41-43. Because PMmin is
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`determined as the minimum value of the signal6 over a predetermined period of M
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`6 While Martin discloses operating on signal power, not magnitude, Apple
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`explained it would have been obvious to adapt Martin to use magnitude when
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`combined with Hirsch. Pet., 34, 40; Ex. 1003, ¶23. Andrea does not contest this.
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`samples, so is Pn(i) because it is set equal to PMmin. Pet., 46-47. Thus, the
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`assignment Pn(i)=PMmin satisfies claim 10 as well.
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`Andrea also argues that “the future minimum and current minimum search
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`for a minimum over two different data windows” and therefore they cannot be the
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`same value. Resp., 32. But nothing in any of the claims requires the current and
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`future minimums to be set over different data windows. For example, while claim
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`10 recites determining the “current minimum” within a predetermined period of
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`time, it says nothing about how the “future minimum” is determined, let alone
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`specify that a different data window must be used. Nor do any claims require the
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`current and future minimums to be set to different values. Dr. Douglas admitted
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`that both minimums can have the same value, (Ex. 1026, 47:13-15, 50:13-16), and
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`both can be set based on the minimum of the current period, (id., 49:16-21 (current
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`minimum is the minimum of the current frame), 51:16-21 (future minimum is the
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`minimum of the current frame)).
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`Andrea’s reading of the claims also is inconsistent with the ’345
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`specification, which shows setting the current minimum and the future minimum
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`equal to the same value “Y(n)” calculated during the same period. See Ex. 1001,
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`Fig. 7, blocks 716 & 718 (highlighted below); id., 8:29-36.
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`Thus, Andrea’s assertion that the current and future minimums must be set
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`to different values using different parameters is contradicted by the ’345 patent.
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`D. A Skilled Artisan Would Have Combined Hirsch and Martin
`In the Petition, Apple described the similarities between the Hirsch and
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`Martin algorithms, and explained why the skilled artisan reading Hirsch would
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`have been motivated to combine it with features of Martin. Pet., 34-38. In
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`Response, Andrea alleges that Apple failed to set forth a rationale for this
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`combination. Resp., 33. Andrea’s arguments are factually flawed for several
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`reasons.
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`First, Andrea is incorrect that Hirsch “disparages” Martin. Hirsch’s
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`statement that “most” known noise estimation approaches have a disadvantage of
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`requiring “relatively long past segments of noisy speech” would not have
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`discouraged a skilled artisan from combining Hirsch with Martin. Ex. 1023, ¶¶32,
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`36-37. When Hirsch cites Martin, Hirsch also cites to references [3] and [7].
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`Reference [7] is Hirsch’s own work, and it would be odd for an author to
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`“disparage” his own work.
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`To the extent Hirsch is criticizing the cited articles, that criticism would not
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`have been directed at Martin. In Hirsch’s prior article [7], he points out that a
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`variety of windows from 0.250 to 2.0 seconds can be considered for estimating
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`noise in speech. Ex. 1032(Hirsch93), 10. As Dr. Hochwald explains, Hirsch’s
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`prior article recognizes that there is a tradeoff between the accuracy of a noise
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`estimate and the ability to adapt to the noise and that the optimum choice of
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`window depends on the nature of the speech signals being considered. Ex. 1023,
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`¶¶33, 37. The other article Hirsch cites describes a system that requires at least 10
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`seconds of noisy speech. Ex. 1023, ¶35; Ex. 1033(Campernolle), 6 (“Parameter
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`estimates are updated in block mode at regular intervals, typically 30 secs, at which
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`time the histograms are also restarted”), 14 (“histograms are restarted every 10 secs
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`of (presumed) speech”), 15 (discussing “effective time constants of 20 to 50 secs
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`depending on the mixing ratio of speech and silence.”). In comparison to these
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`other cited approaches, the difference between Hirsch’s 0.4 seconds and Martin’s
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`0.625 seconds is trivial. Ex. 1023, ¶¶34-37.
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`Even if Hirsch’s comment is interpreted as criticizing Martin, it does not rise
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`to the level of “teaching away” from Martin. See Ex. 1023, ¶¶32, 36-37
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`(explaining Hirsch’s comment would not discourage a POSA from combining).
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`As Dr. Hochwald explains, “[t]o a person knowledgeable in the arts, the difference
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`between 0.4 seconds and 0.625 seconds is not very significant in capturing speech
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`data. Martin’s algorithm has some advantages in that it had been tested to work
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`well with non-stationary noise. A person of ordinary skill would have considered
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`Martin’s benefits to outweigh the hypothetical cost described by Hirsch.” Ex.
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`1003, ¶129. Hirsch itself describes adding his algorithm into systems that operate
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`on 600 ms segments of speech, and thus, plainly does not believe systems using
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`speech segments longer than 400 ms are incompatible with his algorithm. Ex.
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`1005(Hirsch), 155.
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`Second, Andrea argues that because Hirsch does not present experimental
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`results showing that it performs poorly in non-stationary noise environments, a
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`POSA would not have been motivated to improve Hirsch’s performance in such
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`environments. Resp., 36-38. That Hirsch states it works will in stationary noise
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`environments but is silent about non-stationary environments, suggests that it does
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`not perform well. Ex. 1003, ¶¶131-32. Moreover, as Dr. Hochwald explains, in
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`the field of audio signal processing, “[i]t was standard to attempt to optimize
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`system performance by swapping algorithms or tuning parameters.” See Ex. 1003,
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`¶¶131-32. Even if Hirsch had some ability to track non-stationary noise, the
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`skilled artisan would have been motivated to add in Martin’s algorithm to
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`determine whether it performed better. Ex. 2005, 129:1-23. As the Supreme Court
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`explained, “if a technique has been used to improve one de