UNITED STATES PATENT AND TRADEMARK OFFICE
`_______________
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`
`_______________
`
`REALTEK SEMICONDUCTOR CORPORATION
`Petitioner
`
`v.
`
`ANDREA ELECTRONICS CORPORATION
`
`Patent Owner
`_______________
`
`Case: IPR2015-01393
`
`Patent 6,049,607
`_______________
`
`DECLARATION OF DAVID V. ANDERSON
`
`RTL607_1029-0001
`
`Realtek 607 Ex. 1029
`
`

`
`TABLE OF CONTENTS
`
`I.
`
`II.
`
`Introduction ................................................................................................. 1
`
`Qualifications and Compensation ................................................................ 1
`
`III. Materials Considered ................................................................................... 4
`
`IV. Level of Ordinary Skill in the Art ................................................................ 4
`
`V. My Understanding of Patent Law ................................................................ 5
`A.
`Burden of Proof ................................................................................. 5
`B.
`Anticipation ....................................................................................... 5
`C.
`Obviousness ....................................................................................... 6
`D.
`Claim Construction ............................................................................ 7
`
`VI. The ’607 Patent............................................................................................ 8
`
`VII. Prosecution History of the ’607 Patent......................................................... 9
`
`VIII. Prior Art Analysis .......................................................................................10
`A.
`Chu ...................................................................................................12
`B.
`Chu and Kellermann .........................................................................18
`C.
`Chu (alone or with Kellermann) In View Of Wu ..............................25
`D.
`Chu (alone or with Kellermann) In View Of R. E. Crochiere et
`al, "Multirate Digital Signal Processing", Prentice Hall,
`Englewood Cliffs, N.J. (1983) (“Crochiere”) ....................................38
`Chu and Kellermann In Further View Of Koizumi et al.,
`“Acoustic echo canceller with multiple echo paths”, J. Acoust.
`Soc. Jpn. (E) 10, 1 (1989) (“Koizumi”).............................................39
`Chu and Kellermann In Further View Of Kuo et al., “Multiple-
`Microphone Acoustic Echo Cancellation System with the
`Partial Adaptive Process”, Digital Signal Processing 3, 54-63
`(1993) (“Kuo”) .................................................................................41
`
`E.
`
`F.
`
`IX. Conclusion ..................................................................................................44
`i
`
`RTL607_1029-0002
`
`

`
`Appendix 1 – Curriculum Vitae of David Anderson
`
`Appendix 2 – List of Documents Considered
`
`Appendix A – Ground 1 - Claim Chart For U.S. Patent 6,049,607: Claims 1-4 And
`25-28 Are Unpatentable Under 35 U.S.C. § 103 As Being Obvious Over Chu
`
`Appendix B – Ground 2 - Claim Chart For U.S. Patent 6,049,607: Claims 5, 6, 12,
`29, 30, 36 And 37 Are Unpatentable Under 35 U.S.C. § 103 As Being Obvious
`Over Chu In View Of Wu
`
`Appendix C – Ground 3 - Claim Chart For U.S. Patent 6,049,607: Claims 7 and 31
`Are Unpatentable Under 35 U.S.C. § 103 As Being Obvious Over Chu In View
`Of Crochiere
`
`Appendix D – Ground 4 - Claim Chart For U.S. Patent 6,049,607: Claims 8, 10,
`32, And 34 Are Unpatentable Under 35 U.S.C. § 103 As Being Obvious Over
`Chu In View Of Kellermann
`
`Appendix E – Ground 5 - Claim Chart For U.S. Patent 6,049,607: Claims 9 And 33
`Are Unpatentable Under 35 U.S.C. § 103 as Being Obvious Over Chu And
`Kellermann In Further View Of Koizumi
`
`Appendix F – Ground 6 - Claim Chart For U.S. Patent 6,049,607: Claims 11 And
`35 Are Unpatentable Under 35 U.S.C. § 103 As Being Obvious Over Chu And
`Kellermann In Further View of Kuo
`
`Appendix G – Ground 7 - Claim Chart For U.S. Patent 6,049,607: Claims 1-4, 8,
`10, 25-28, 32, And 34 Are Unpatentable Under 35 U.S.C. § 103 As Being
`Obvious Over Kellerman In View Of Chu
`
`ii
`
`RTL607_1029-0003
`
`

`
`I, David V. Anderson, hereby declare, affirm and state the following:
`
`I.
`
`1.
`
`Introduction
`
`The facts set forth below are known to me personally, and I have firsthand
`
`knowledge of them.
`
`2.
`
`I make this Declaration in support of a Petition for inter partes review of
`
`U.S. Patent No. 6,049,607 (“the ’607 Patent”).
`
`3.
`
`I have been retained by Steptoe & Johnson LLP on behalf of Realtek
`
`Semiconductor Corporation.
`
`4.
`
`I have been asked to provide my technical review, analysis, insights, and
`
`opinions on the materials I have reviewed in this case related to the ’607 Patent,
`
`including the references that form the basis for the grounds of rejection set forth in
`
`Petition No. IPR2015-01393 for Inter Partes Review of the ’607 Patent
`
`(“Petition”), and the scientific and technical knowledge regarding the same subject
`
`matter at the time of the alleged inventions disclosed in the ’607 Patent.
`
`II. Qualifications and Compensation
`
`5.
`
`6.
`
`I am over the age of eighteen and I am a citizen of the United States.
`
`I have summarized in this section my educational background, career
`
`history, and other relevant qualifications. My curriculum vitae, including my
`
`qualifications, a list of the publications that I have authored during my technical
`
`1
`
`RTL607_1029-0004
`
`

`
`career, and a list of the cases in which, during the previous four years, I have
`
`testified as an expert at trial or by deposition, is attached to this declaration as
`
`Appendix 1.
`
`7.
`
`I earned my Bachelor of Science degree in Electrical Engineering from
`
`Brigham Young University in 1993. In 1994 I earned my Master of Science
`
`degree in Electrical Engineering, also from Brigham Young University. I earned
`
`my Doctorate of Philosophy in Electrical and Computer Engineering from Georgia
`
`Institute of Technology in 1999, with my dissertation on “Audio Signal
`
`Enhancement Using Multi-resolution Sinusoidal Modeling.”
`
`8.
`
`After obtaining my Doctorate of Philosophy degree, I worked as an
`
`Education Specialist at Texas Instruments, Inc. from April 1999 through
`
`September of 1999. In this position, I developed a self-paced course on signal
`
`processing fundamentals and implementation for practicing engineers.
`
`9.
`
`In September of 1999, I joined the faculty of Georgia Institute of
`
`Technology as an Assistant Professor in the School of Electrical and Computer
`
`Engineering. While on this faculty, I taught courses in signal processing and
`
`computer architecture and performed research in signal processing and low-power
`
`implementation of signal processing systems.
`
`2
`
`RTL607_1029-0005
`
`

`
`10.
`
`In June of 2005, I was promoted to the rank of Associate Professor, and in
`
`March of 2012, I became a full Professor, where I continued teaching and research
`
`in signal processing and signal processing systems with an emphasis in low-power
`
`systems, signal enhancement, and signal processing related to human audio
`
`perception.
`
`11.
`
`I have authored and co-authored approximately 200 journal publications,
`
`conference proceedings, technical articles, technical papers, book chapters, and
`
`technical presentations, in a broad array of signal processing technology. I have
`
`also developed and taught over many courses related to digital signal processing
`
`and signal processing systems. These courses have included introductory as well
`
`as more advanced courses.
`
`12.
`
`I have three patents related to the field of audio signal enhancement, U.S.
`
`Patent no. 6,351,731; U.S. Patent no. 6,453,285; and U.S. Patent no. 7,034,603.
`
`Additionally, I have many scholarly publications on enhancing speech signals and
`
`removing noise that are included in my CV including J. M. Hurtado and D. V.
`
`Anderson “FFT-based block processing in speech enhancement: potential artifacts
`
`and solutions,” IEEE Transactions on Audio, Speech, and Language Processing,
`
`19(8):2527-2537, Nov. 2011.
`
`3
`
`RTL607_1029-0006
`
`

`
`13.
`
`I am being compensated for my time at the rate of $350 per hour for my
`
`work in connection with this matter. The compensation is not dependent in any
`
`way on the contents of this Declaration, the substance of any further opinions or
`
`testimony that I may provide, or the ultimate outcome of this matter.
`
`III. Materials Considered
`
`14.
`
`I have carefully reviewed the ’607 Patent and its file history. I have also
`
`reviewed several prior art references.
`
`15.
`
`For convenience, all of the sources that I considered in preparing this
`
`declaration are listed in Appendix 2.
`
`IV. Level of Ordinary Skill in the Art
`
`16.
`
`I have been informed that my analysis of the interpretation of the asserted
`
`claims of the ’607 patent must be undertaken from the perspective of a person
`
`possessing ordinary skill in the art of the ’607 patent. In my opinion, a person of
`
`ordinary skill in the art at the time of the ’607 patent would have been an
`
`individual with at least training at the Masters degree in Electrical Engineering
`
`with a specialty in digital signal processing. In the alternative, this person would
`
`have a Bachelor’s degree in Electrical Engineering with at least two years of
`
`training in signal processing specializing in adaptive signal processing, and at least
`
`two years of experience with microphone array processing algorithm development
`
`4
`
`RTL607_1029-0007
`
`

`
`and implementation. I possess these qualifications, and I have considered the issues
`
`herein from the perspective of a person of ordinary skill in the art.
`
`V. My Understanding of Patent Law
`
`17.
`
`I am not an attorney but I have had the concept of patentability explained to
`
`me. I understand that a patent claim can be unpatentable under the United States
`
`patent laws for various reasons, including, for example, anticipation or obviousness
`
`in light of the prior art. In arriving at my opinions, I have applied the following
`
`legal standards and analyses regarding patentability.
`
`A.
`
`Burden of Proof
`
`18.
`
`I understand that Petitioner has the burden to prove a proposition of
`
`unpatentability by a preponderance of the evidence. I also understand that this is a
`
`lower standard than the clear and convincing evidence standard that is required to
`
`prove unpatentability in patent litigation before a district court.
`
`B.
`
`Anticipation
`
`19.
`
`I understand that a claim is anticipated by a prior art reference if the prior art
`
`reference discloses every element in the claim. Such a disclosure can be express (it
`
`says or shows it), or it can be inherent (the element must necessarily be there even
`
`if the prior art does not say it or show it). If the claim is anticipated, the claim is
`
`unpatentable.
`
`RTL607_1029-0008
`
`5
`
`

`
`20.
`
`I understand that the first step in an anticipation analysis is to construe the
`
`claim, and the second step is to compare the construed claim to the prior art
`
`reference.
`
`C.
`
`Obviousness
`
`21.
`
`I understand that a patent claim may be unpatentable for obviousness even if
`
`it is not anticipated by the prior art. I understand that a patent claim is obvious if
`
`the differences between the claimed intervention and the prior art are such that the
`
`subject matter of the claimed invention, as a whole, would have been obvious to
`
`one of ordinary skill in the art at the time the invention was made. If the claim is
`
`obvious, the claim is unpatentable.
`
`22.
`
`I understand that before an obviousness determination is made, the level of
`
`ordinary skill in the art must be considered, and the scope and content of the prior
`
`art must be considered, as well. I understand that to determine the scope and
`
`content of prior art, one must determine what prior art is reasonably pertinent to the
`
`particular problem the inventor faced. I understand that prior art is reasonably
`
`pertinent if it is in the same field as the claimed invention, or is from another field
`
`that a person of ordinary skill in the art would look to in trying to solve the
`
`problem.
`
`6
`
`RTL607_1029-0009
`
`

`
`23.
`
`I understand that a patent claim maybe be obvious if the prior art would have
`
`suggested, motivated, or provided a reason to one of ordinary skill in the art to
`
`combine certain prior art references to arrive at the elements of the claim. I also
`
`understand that one can look at interrelated teachings of multiple patents, the
`
`effects of demands known to the design community or present in the marketplace,
`
`and the background knowledge possessed by a person having ordinary skill in the
`
`art—all in order to determine whether there was an apparent reason to combine the
`
`known elements in the fashion claimed by the patent at issue. I further understand
`
`that a person of ordinary skill is a person of ordinary creativity, not an automaton.
`
`This person of ordinary creativity works in the contexts of a community of
`
`inventors and of the marketplace. The obviousness inquiry needs to reflect these
`
`realities within which inventions and patents function. In order to arrive at a
`
`conclusion that an invention is obvious, it can be helpful to identify a reason that
`
`would have prompted a person of ordinary skill in the relevant field to combine the
`
`elements in the way the claimed invention does.
`
`D.
`
`Claim Construction
`
`24.
`
`For the purposes of my opinions related to the issue of patentability of the
`
`’607 Patent, I have been informed that the claims of the ’607 Patent are to be given
`
`their broadest reasonable interpretation in view of the specification from the
`
`7
`
`RTL607_1029-0010
`
`

`
`perspective of one skilled in the art. In comparing the claims of the ’607 Patent to
`
`the known prior art, I have carefully considered the ’607 Patent and the ’607 Patent
`
`prosecution history based upon my experience and knowledge in the relevant field.
`
`25.
`
`For the reasons explained below, claims 1-12 and 25-37 of the ’607 patent
`
`are unpatentable as being obvious by the prior art discussed below. I reserve the
`
`right to amend and/or supplement this declaration in light of additional relevant
`
`evidence, arguments, or testimony presented, for example, during discovery for
`
`this IPR.
`
`VI. The ’607 Patent
`
`26.
`
`The ’607 Patent describes an apparatus and method for echo-cancelling in a
`
`full duplex communication system like a teleconference. A teleconference
`
`typically involves sounds present at a “near-end” location, such as those of a near-
`
`end loudspeaker, that are received by one or more microphones. These sounds are
`
`transmitted to a “far-end” system (i.e. a phone system located at a second location)
`
`and subsequently broadcast by a far-end loudspeaker. At the far-end system,
`
`sounds emanating from the far-end loudspeaker are also received by the far-end
`
`microphone and transmitted to the near-end system where they are broadcast by
`
`the near-end loudspeaker. As a result, a disturbing echo will be heard in the
`
`system. Without an echo cancellation mechanism in the system, a person speaking
`
`8
`
`RTL607_1029-0011
`
`

`
`into the microphone will hear himself as a result of his or her voice being
`
`transmitted over the far-end loudspeaker, into the far-end microphone and back out
`
`of the near-end loudspeaker.
`
`27.
`
`The ’607 Patent specifically describes cancelling echoes in the system by (1)
`
`splitting (through splitter 114) the near-end signal from microphone array 102 and
`
`far-end signal (through splitter 128) and (2) adaptively filtering the interference
`
`signal from the target signal through adaptive filters 116x. See Ex. 1001, Fig. 1.
`
`28.
`
`Splitting and adaptively filtering signals was well known prior to the filing
`
`of the application that led ’607 Patent as admitted in the “Background of the
`
`Invention” section of the ’607 Patent. See id. at 1:22-3:27.
`
`VII. Prosecution History of the ’607 Patent
`
`29.
`
`The ’607 Patent was filed on September 18, 1998, and issued with no
`
`rejections. Ex. 1020 at pp. 62-69 (RTL607_1020-0062-69). On December 3,
`
`1999, the Examiner allowed all claims and stated in his reasons for allowance that
`
`the prior art of record taken alone and in combination does not disclose the “beam
`
`splitter” limitation recited in claim 1 (i.e., “a beam splitter for beam-splitting said
`
`target signal . . . whereby for each band-limited target signal there is a
`
`corresponding band-limited interference signal.”). Id. The Examiner also indicated
`
`that he had called Applicants’ representative that same day, December 3, to discuss
`
`9
`
`RTL607_1029-0012
`
`

`
`some “minor informalities” in claims 1, 13 and 25. Id. at p. 68 (RTL607_1020-
`
`0068). The Applicants agreed to an Examiner’s amendment changing “equals” to
`
`“equal” in these claims. Id. at pp. 25 (see handwritten changes) (RTL607_1020-
`
`0025). The ’607 Patent issued on April 11, 2000. Id. (RTL607_1021-0081).
`
`VIII. Prior Art Analysis
`
`30.
`
`I now turn to the references applied in the grounds for rejections discussed in
`
`the Petition for inter partes review. In my analysis, I will specifically address the
`
`following references:
`
`Reference
`No.
`1022 U.S. Patent No. 5,263,019
`1023 U.S. Patent No. 6,125,179
`1024 R. E. Crochiere et al., “Multirate Digital Signal
`Processing”, Prentice Hall, Englewood Cliffs,
`N.J. (1983)
`1025 Walter Kellermann, “Strategies for Combining
`Acoustic Echo Cancellation and Adaptive
`Beamforming Microphone Arrays” (1997)
`1026 Nobuo Koizumi et al., “Acoustic echo
`canceller with multiple echo paths”, J. Acoust.
`Soc. Jpn. (E) 10, 1 (1989)”
`Sen M. Kuo and Jier Chen, “Multiple-
`Microphone Acoustic Echo Cancellation
`
`1027
`
`Referred To As
`Chu
`Wu
`Crochiere
`
`Kellerman
`
`Koizumi
`
`Kuo
`
`10
`
`RTL607_1029-0013
`
`

`
`No.
`
`Reference
`System with the Partial Adaptive Process”,
`Digital Signal Processing 3, 54-63 (1993)
`Miyamoto
`1028 U.S. Patent No. 4,894,820
`31.
` Attached hereto as Appendices A-K are claim charts addressing each of the
`
`Referred To As
`
`above references, alone or in a combination with another reference. I have
`
`reviewed the charts in detail and incorporate the charts herein by reference.
`
`32.
`
`In my opinion, what is being described in claim 1 of the ’607 Patent is a (1)
`
`microphone input for inputting a signal representing speech generated at a near end
`
`of a teleconference and (2) a speaker signal input for inputting the transmitted
`
`audio received from the microphone at the far end of the communication system,
`
`which is used to estimate the echo, or interference, contained in the (near-end)
`
`microphone signal. Although claim 1 does not define a “reference signal,” this
`
`term appears in claim 2 as “said reference signal”1 and is defined as the signal
`
`received from the far end which is then broadcast at the near end and is the source
`
`of an echo signal, or “interference signal,” that is filtered from the microphone
`
`input signal by the adaptive filter. In my opinion, at least the second and third
`
`1 I understand that the use of the phrase “said” before a term requires that term to
`
`be previously introduced. The phrase “said” may be a typographical mistake.
`
`11
`
`RTL607_1029-0014
`
`

`
`limitations 2 of claims 1 and 25 must utilize the reference signal—not the
`
`interference signal, which is derived from, or a function of, the reference signal.
`
`33.
`
`For purposes of my analysis of the prior art, I will substitute the term
`
`“reference signal” for “interference signal” in claims 1 and 25.
`
`A.
`
`Chu
`
`34. U.S. Patent No. 5,263,019 (“Chu”), which is attached to the Petition as
`
`Exhibit 1022 renders obvious (in view of the ordinary skill in the art or with other
`
`prior art references) at least claims 1–12, 25-37 of the ’607 Patent.
`
`35. At a general level, Chu is directed to reducing unwanted audio or acoustic
`
`feedback (or echo) in a communication system. See Ex. 1022 at 1:15-20. A main
`
`goal of Chu is to provide an adaptive acoustic echo cancellation device for
`
`suppressing acoustic feedback between the loudspeaker and microphone of a
`
`telephone unit in a teleconferencing system. See id. at 3:23-31; Fig. 1. To achieve
`
`this goal, an echo estimation signal is subtracted from the microphone signal to
`
`produce an echo corrected microphone signal. Id. at 5:12-31; 7:64-68:5; Fig. 1.
`
`2 The second and third limitations refer to the “reference input” and “beam splitter”
`
`limitations.
`
`RTL607_1029-0015
`
`12
`
`

`
`36.
`
`There are two inputs in Chu. The first input is the microphone 10, which
`
`converts near-end speech, corrupted by acoustic echo, into a microphone signal.
`
`See, e.g., Ex. 1022 at 4:49-63; 6:42-47; 10:34-41; see also Figure 1. In my
`
`opinion, the microphone input is the target signal as recited in claims 1-2 and 25-
`
`26 of the ’607 Patent.
`
`Ex. 1022, FIG. 1 (annotated) (emphasized in red highlight).
`
`37.
`
`The second input is the digitized electronic speaker signal, (cid:1871)(cid:4666)(cid:1878)(cid:4667)(cid:481) which is
`
`used to derive loudspeaker signal 32 and which represents the voices of people at a
`
`far end of the communication system and is used to estimate the echo contained in
`
`the microphone signal. See id. at 1:24-26; 4:65- 5:7; see also id., Figure 1. In my
`
`opinion, s(z) is the “interference signal” (which I am referring to as the “reference
`
`signal”) in claim 1 and 25 and the “reference signal” as properly used in claim 2,
`
`26, and their dependent claims in the ’607 Patent.
`
`13
`
`RTL607_1029-0016
`
`

`
`Ex. 1022, FIG. (annotated) (emphasized in red highlight).
`
`38.
`
`Chu discloses that the digitized microphone signal, m(z), is passed through a
`
`whitening filter and then applied to a splitter 16 which separates the signal into
`
`twenty-nine distinct frequency bands. See id. at 5:8-16; see also id., Figure 1.
`
`Ex. 1022, FIG. 1 (annotated) (emphasized in red highlight).
`
`14
`
`RTL607_1029-0017
`
`

`
`39.
`
` Similarly, the loudspeaker signal, s(z), is whitened and band filtered,
`
`through a signal splitter 30, in the same manner as the microphone signal, into
`
`twenty-nine bandpass loudspeaker signals. See id. at 5:25-31; see also id., Figure
`
`1.
`
`Ex. 1022, FIG. 1 (annotated) (emphasized in red highlight).
`
`40.
`
`The amount of bandpass microphone signals (twenty-nine) is therefore the
`
`same as the amount of bandpass loudspeaker signals such that each bandpass
`
`microphone signal corresponds with each bandpass loudspeaker signal. See e.g. id.
`
`Fig. 1. The loudspeaker signals are separated into the same frequency bands as the
`
`microphone signals. Id. at 7:32-37; 7:64- 8:4. Thus, both the amount and
`
`frequency of the band-limited microphone and band-limited loudspeaker signals
`
`are equal.
`
`RTL607_1029-0018
`
`15
`
`

`
`41. Although Chu does not describe a “beam splitter,” it would have been
`
`obvious for one of ordinary skill in the art to implement the system of Chu using a
`
`splitter capable of splitting a beam (what the ’607 Patent refers to as a “beam
`
`splitter”). Splitting beams was well known in the art as shown in, for example,
`
`Kellermann below. Ex. 1025 at p. 2, Figure 2 (showing a plurality of beams is
`
`selected for adaptive filtering by the Acoustic Echo Canceller (AEC-I) and
`
`subtractor);
`
`id. at p. 1, § 2. “Generic Concepts”
`
`
`
`(describing
`
`that
`
`“fullband/subband/transform domain structures” are used for signal splitting (e.g.
`
`to subbands) of the beams before the adaptive filtering) (RTL607_1025-0001-2).
`
`In my opinion, if a person of ordinary skill in the art wished to utilize a beam,
`
`instead of a non-directional signal, in Chu’s system, it would have been obvious to
`
`implement a beam splitter, which was well known in the art, instead of the regular
`
`signal splitter disclosed in Chu. Alternatively, in my opinion, the “splitter”
`
`described in Chu is broad enough to include a specific type of splitter like the
`
`claimed “beam splitter.” The’607 Patent uses the term “splitter” and “beam
`
`splitter” (as well as the terms “splitting” and “beam splitting”) interchangeably.
`
`While Claims 1 and 25 include limitations directed to a “beam splitter” for “beam-
`
`splitting” the interference (reference) signal, there is no indication in the Claims or
`
`the specification that the interference (reference) signal is a beam. In fact, the
`
`16
`
`RTL607_1029-0019
`
`

`
`specification of the’607 Patent describes that a splitter – not a beam splitter – is
`
`used to split the interference/reference signal. See Ex. 1001, Fig. 1; see also id. at
`
`5:63-67 (“Meanwhile, the far end signal (referred to as the reference channel) is
`
`…conditioned, sampled, decimated and split in the manner discussed above by…
`
`splitter 128”). (Emphasis added).
`
`42.
`
`Chu further discloses an adaptive filter bank 18 which includes an adaptive
`
`filter for each bandlimited microphone signal. Ex. 1022 at 7:64-67; Figs. 1 and 3.
`
`Each adaptive filter estimates the echo in a corresponding band and removes the
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`estimated echo from the corresponding bandlimited microphone signal. Id. at
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`7:64-8:4. In my opinion, adaptive filter bank 18 is the adaptive filter array in claim
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`3 of the ’607 Patent.
`
`Ex. 1022, FIG. 1 (annotated) (emphasized in red highlight).
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`17
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`RTL607_1029-0020
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`
`43.
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`Chu also discloses that the transfer characteristics of the adaptive filter are
`
`adjusted to reduce the echo in the echo corrected microphone signal. Id. at 3:31-
`
`43.
`
`B.
`
`Chu and Kellermann
`
`44.
`
`The features in claims 1-4, 8, 10, 25-28, 32 and 34 of the ’607 Patent are
`
`unpatentable as being obvious over Kellermann, “Strategies for Combining
`
`Acoustic Echo Cancellation and Adaptive Beamforming Microphone Arrays”
`
`(1997) (“Kellermann”), which is attached to the Petition as Ex. 1025, in view of
`
`Chu (and the features in claims 8, 10, 32, and 34 are also unpatentable as being
`
`obvious over Chu in view of Kellermann).
`
`45.
`
`Like the ’607 Patent, an objective of Kellermann is to provide an efficient
`
`echo canceller (EC) “which models the impulse response of the loudspeaker –
`
`enclosure – microphone system by an adaptive filter in order to remove echo
`
`components from the microphone signal” See Ex. 1025 at p. 1 §1. “Introduction”
`
`(RTL607_1025-0001). To achieve this objective, echo canceller of Kellermann
`
`may include “fullband/subband/transform domain structures” for signal splitting
`
`(e.g. to subbands) and an “adaptation algorithm” for the acoustic echo canceller.
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`Id. at p. 1 § 2. “Generic Concepts” (RTL607_1025-0001).
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`18
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`RTL607_1029-0021
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`
`46.
`
`Figure 1 in Kellermann shows an input into the microphone array from local
`
`talkers for inputting the microphone signal which contains the echo components.
`
`See also id. at p. 1; Figure 1 (RTL607_1025-0001). In my opinion, the
`
`microphone input or the output of the beamformer (i.e., Fixed BF, Control and
`
`Mapping) could be the target signal in claims 1 and 25, and the echo components
`
`are the interference signal as recited in claims 2 and 26 of the’607 Patent.
`
`Ex. 1025, Figure 2 (annotated) (emphasized in red highlight) (RTL607_1025-
`
`0002).
`
`47.
`
`Figure 1 in Kellermann also shows a far-end speech signal. See also Ex.
`
`1025 at p. 1; Figure 2 (RTL607_1025-0001-2). In my opinion, the far-end speech
`
`signal is the “interference signal” (which I am referring to as the “reference signal”
`
`in my analysis) in claim 1 and 25 and the “reference signal” as properly used in
`19
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`RTL607_1029-0022
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`
`claim 2, 26, and their dependent claims in the ’607 Patent. The far-end speech
`
`signal must be input into the local system shown in Figure 2 through reference
`
`input that is not shown.
`
`Ex. 1025, Fig. 2 (annotated) (emphasized in red highlight).
`
`48. Adaptive filters are also key components of Kellermann and Chu. Ex. 1025
`
`at p. 1 (RTL607_1025-0001); Ex. 1022 at 7:64-8:4. Kellermann generally
`
`describes that echo components are removed from the microphone signal by an
`
`adaptive filter. Ex. 1025 at p. 1 (RTL607_1025-0001). Kellermann further
`
`discloses that the impulse response of the system, including the loudspeaker, is
`
`modeled by the adaptive filter. In my opinion, modeling impulse response by the
`
`adaptive filter is slightly different terminology, as understood by one of ordinary
`20
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`RTL607_1029-0023
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`
`skill in the art, of describing estimating a transfer function of the reference signal
`
`as recited in claim 4 of the ’607 Patent. Id.
`
`49. A person of ordinary skill in the art would be motivated to combine Chu and
`
`Kellermann because both references describe reducing acoustic echo in voice
`
`communication systems using adaptive filters. Ex. 1022 at 1:15-20; 3:23-31; Fig.
`
`1; Ex. 1025 at p. 1-2, Fig. 2 (RTL607_1025-0001-2). Both prior art references
`
`describe that signals are selected for adaptive filtering. Ex. 1022 at 7:64- 8:4; Ex.
`
`1025 at p. 2, Fig. 2 (RTL607_1025-0002). Chu provides specific detail relating to
`
`both the adaptive filter and splitter that is generally described in Kellermann. See
`
`e.g. Ex. 1022 at 7:64-67, Fig. 3; Ex. 1025 at p. 1 § 2 (RTL607_1025-0001).
`
`“Generic Concepts.” However, whereas Chu does not specifically describe the
`
`selection of beam signals, Kellermann provides beam selection prior to the
`
`adaptive filtering of beams. Ex. 1025 at p. 2 (RTL607_1025-0002). In my
`
`opinion, it would have been obvious to combine Kellermann’s beam selection and
`
`simultaneous adaptive filtering of beams with Chu in order for Chu’s system to
`
`process one or more beam signals. Combining these references would allow Chu’s
`
`system to utilize an array of microphones inputting beam signals.
`
`50. While Chu does not specifically address selecting beams for adaptive
`
`filtering as recited in claim 8 of the ’607 Patent, Kellermann does teach that at least
`
`21
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`RTL607_1029-0024
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`
`one of a plurality of beams is selected for adaptive filtering by the Acoustic Echo
`
`Canceller (AEC-I) and subtractor. Ex. 1025 at p.2, id., Fig. 2 (RTL607_1025-
`
`0002). Specifically, Kellermann describes that M fixed-beam signals are mapped
`
`onto L “talker beams” and that the mapping should select one fixed beam or a
`
`linear combination of two neighboring fixed beams per talker. Id. By definition, a
`
`beam must have a direction. Kellermann recognizes the need to have a
`
`microphone array (MA) directing a beam of increased sensitivity at the active
`
`talker. Id. at p. 1 (RTL607_1025-0001). The fixed beams in Kellermann are
`
`beams from different directions. Kellermann discloses that beam(s) in the
`
`direction of the active talker are selected for processing. In my opinion, the beams
`
`therefore represent a direction from which the main signal (talker) is received as
`
`recited in claim 8 of the ’607 Patent.
`
`51.
`
`Figure 2 of Kellermann shows that AEC-I and the subtractor, which
`
`constitute the adaptive filter, receive more than one mapped signal (the thick arrow
`
`represents more than one signal). The L at the output of the subtractor indicates
`
`that there are L “talker beams” selected for processing by the AEC resulting in an
`
`L-channel AEC problem. In particular, Kellermann specifies “To minimize the
`
`number of signals for the AEC, we introduce a mapping of the M fixed-beam
`
`signals onto L ‘talker beams’ whenever (cid:1838) (cid:3407) (cid:1839) (cid:3407) (cid:1840).” Id. at p. 3§ 3.2 “AEC with
`
`22
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`RTL607_1029-0025
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`

`
`BF-I” (RTL607_1025-0002-3). Therefore, the AEC-I selects L beams (a “plurality
`
`of beams”) for simultaneous adaptive filtering operations as recited in claim 10 of
`
`the ’607 Patent.
`
`Ex. 1025 at p. 2, Fig. 2 (annotated) (emphasized in red highlight) (RTL607_1025-
`
`0002).
`
`52. Notably, Kellermann describes various beamforming methods (i.e., fixed
`
`beamforming and adaptive beamforming) which take place prior to mapping and
`
`adaptive filtering (AEC-I). Figures 2 and 3 show the fixed beamformer (BF) and
`
`adaptive BF:
`
`23
`
`RTL607_1029-0026
`
`

`
`Ex. 1025 at pp. 2-3, Figures 2-3 (annotated) (emphasized in red highlight)
`
`(RTL607_1025-0002-3).
`
`53. Kellermann further discloses that the AEC-1 in Figure 2, reproduced below,
`
`adaptively filters multiple beams as recited in claim 10 of the ’607 Patent.
`
`Specifically, Kellermann’s adaptive filter (AEC-I and the subtractor) processes
`
`each of the outputs of the mapping. Specifically, L beams are output from the
`
`mapping block and passed onto the AEC.
`
`24
`
`RTL607_1029-0027
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`

`
`Ex. 1025 at p. 2, Fig. 2 (annotated) (emphasized in red highlight) (RTL607_1025-
`
`0002).
`
`C.
`
`Chu (alone or with Kellermann) In View Of Wu
`
`54.
`
`To the extent that elements of the claims 5, 6, 12, 29, 30, 36, and 37 are not
`
`expressly disclosed in Chu (alone