Case: 18-2382 Document: 45 Page: 1 Filed: 02/07/2020
United States Court of Appeals
for the Federal Circuit
______________________
APPLE INC.,
Appellant
v.
ANDREA ELECTRONICS CORPORATION,
Appellee
______________________
2018-2382, 2018-2383
______________________
Appeals from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in Nos. IPR2017-
00626, IPR2017-00627.
______________________
Decided: February 7, 2020
______________________
JEFFREY PAUL KUSHAN, Sidley Austin LLP, Washing-
ton, DC, argued for appellant. Also represented by THOMAS
ANTHONY BROUGHAN, III, CHRISTIN SULLIVAN MILLER.
WILLIAM D. BELANGER, Pepper Hamilton LLP, Boston,
MA, argued for appellee. Also represented by BRADLEY
THOMAS LENNIE, GOUTAM PATNAIK, Washington, DC.
______________________
Before DYK, PLAGER, and STOLL, Circuit Judges.
PLAGER, Circuit Judge.
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2 APPLE INC. v. ANDREA ELECS. CORP.
The patent at issue in this appeal, U.S. Patent No.
6,363,345 (“the ’345 patent”), relates to certain aspects of
digital audio processing. On September 19, 2016, Andrea
Electronics Corp. (“Andrea or Appellee”), assignee of the
’345 patent, sued Apple, Inc. (“Apple or Appellant”) for in-
fringement of the ’345 patent in the Eastern District of
New York. J.A. 1151–70. On January 9, 2017, Appellant
Apple filed two inter partes review (“IPR”) petitions—the
’626 IPR and ’627 IPR—with the U.S. Patent and Trade-
mark Office, challenging the validity of claims 1–25 and
38–47 of the patent.
The Patent Trial and Appeal Board (“Board”) insti-
tuted review of both petitions and consolidated the pro-
ceedings. In its ’626 IPR Final Written Decision, the Board
concluded that, in light of the prior art cited by Apple, all
challenged claims except claims 4–11 and 39–47 of the ’345
patent are unpatentable. In the course of reaching that
conclusion, the Board declined to consider certain argu-
ments in Apple’s ’626 IPR reply brief applicable to claims
6–9 on the ground that Apple was raising new arguments
in its reply brief that were not entitled to consideration at
that late stage in the proceedings.
In its ’627 IPR Final Written Decision, the Board con-
cluded that, in light of other cited art, all challenged claims
of the ’345 patent except claims 6–9, 17–20, 24, and 47 are
unpatentable. In reaching that conclusion, the Board
adopted a claim construction of the claim term “periodi-
cally” in favor of Andrea that supported its analysis. Be-
tween the two IPRs, the Board held that all challenged
claims except claims 6–9 are unpatentable.
With regard to the ’626 IPR Board decision, Apple ap-
peals the Board’s conclusion that claims 6–9 are surviving
claims, arguing that had the Board properly considered its
reply brief arguments, that would not have been the out-
come. With regard to the ’627 IPR Board decision, Apple
argues that the Board erred in its conclusion that, based on
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APPLE INC. v. ANDREA ELECS. CORP. 3
the prior art cited, claims 6–9 are not unpatentable as ei-
ther anticipated or obvious.
With respect to the ’626 IPR, for the reasons we shall
explain, we conclude that the Board erred in refusing to
consider Apple’s reply arguments. Accordingly, we vacate
the Board’s decision in the ’626 IPR, and remand for recon-
sideration of Apple’s reply brief arguments addressing the
indicated prior art reference.
With respect to the ’627 IPR, we find that the Board’s
decision with regard to the validity of the patent claims in
its ’627 IPR Final Written Decision was correctly reached.
We therefore affirm the Board with respect to the ’627 IPR.
I. BACKGROUND
A. Digital Audio Processing
Because an understanding of the issues and our dispo-
sition of them require some familiarity with the technology
of sound and digital audio processing, we begin with that.
Sound is the physical vibrations of a medium, such as air.
These vibrations are often depicted in the form of a sinus-
oidal wave, a “sine wave,” with time on the x-axis (horizon-
tal), and the amplitude of the signal (roughly, volume) on
the y-axis (vertical).
J.A. 833.
In addition to the amplitude, the frequency (cycles per pe-
riod of time) of a sound wave is a particularly relevant
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4 APPLE INC. v. ANDREA ELECS. CORP.
factor for human hearing. While amplitude roughly corre-
sponds to volume, frequency corresponds to the pitch of the
sound.
Music and speech are generally comprised of sound at
different frequencies (e.g., a musical chord consists of sev-
eral notes played simultaneously). When multiple notes
are played at the same time, the graphical representation
of the resulting signal may look different from a simple sine
wave:
J.A. 836. The resulting graph is a composite of several dif-
ferent sine waves, each corresponding to an individual fre-
quency and amplitude. To determine which frequencies
make up the signal, the signal can be converted to the fre-
quency domain via a well-known mathematical formula
called a “Fourier transform.”
Digital signal processing frequently uses Fourier
transforms to convert sounds between the time domain and
frequency domain because it is computationally easier to
make certain modifications to the signal in the frequency
domain than in the time domain. This conversion to the
frequency domain results in a histogram, in which the sig-
nal is divided into “frequency bins” and each bin corre-
sponds to one of the frequencies present in the signal. The
magnitude of a particular frequency is represented on the
y-axis.
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APPLE INC. v. ANDREA ELECS. CORP. 5
B. The ’345 Patent
The patent at issue, the ’345 patent, describes a
method, system, and apparatus that utilizes Fourier trans-
forms and a process known as “spectral subtraction” for
noise cancellation and reduction purposes. The disclosed
system converts an audio signal to the frequency domain
via Fourier transforms, sets separate thresholds for each
“frequency bin” in order to distinguish the background
noise, and then employs “spectral subtraction” to remove
ambient noise without affecting speech and its characteris-
tics. ’345 patent, col. 6 ll. 10–13.
In order to determine the appropriate threshold for
each frequency bin, the system sets two minimum values,
which are described as a “future minimum” and a “current
minimum.” ’345 patent, col. 6 ll. 23–41. At predetermined
time intervals (e.g., every five seconds), the future mini-
mum value is initialized as the value of the current magni-
tude of the signal. ’345 patent, col. 6 ll. 24–28. Over that
time interval, the future minimum is compared with the
current magnitude value of the signal. If the observed
magnitude is less than the value of the future minimum,
then the future minimum is set equal to that newly ob-
served lower value. ’345 patent, col. 6 ll. 24–32.
At the start of each time interval, the current minimum
is set as the value of the future minimum that was deter-
mined over the previous time interval. ’345 patent, col. 6
ll. 34–38. The current minimum value then follows the
minimum value of the signal over the next time interval by
comparing its value with the current magnitude value.
’345 patent, col. 6 ll. 34–38. The final current minimum
value is used to calculate the adaptive threshold.
This adaptive threshold is used in a process known as
“spectral subtraction,” in which the value of the estimated
“noise magnitude” is subtracted from the current magni-
tude value of the bin. The result is a cleaner signal with
some of the noise removed.
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6 APPLE INC. v. ANDREA ELECS. CORP.
C. The Claims at Issue
Claims 6–9 of the ’345 patent are the only claims at is-
sue in this appeal. Claims 6–9 depend from claim 5, which
depends from claim 4, which depends from claim 1:
1. An apparatus for cancelling noise, comprising:
An input for inputting an audio signal which in-
cludes a noise signal;
A frequency spectrum generator for generating the
frequency spectrum of said audio signal thereby
generating frequency bins of said audio signal; and
A threshold detector for setting a threshold for each
frequency bin using a noise estimation process and
for detecting for each frequency bin whether the
magnitude of the frequency bin is less than the cor-
responding threshold, thereby detecting the posi-
tion of noise elements for each frequency bin.
’345 patent, col. 9 ll. 34–46 (emphasis added).
Claim 4 adds features to the threshold detector, noting
that the threshold detector “sets the threshold for each fre-
quency bin in accordance with a current minimum value of
the magnitude of the corresponding frequency bin; said
current minimum value being derived in accordance with
a future minimum value of the magnitude of the corre-
sponding frequency bin.” ’345 patent, col. 9 ll. 54–60.
Claim 5 adds that the “future minimum value is de-
termined as the minimum value of the magnitude of the
corresponding frequency bin within a predetermined pe-
riod of time.” Thus claims 6–9 depend ultimately from
claim 5, and place specific limits on how the “current min-
imum value” or “future minimum value” are determined.
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APPLE INC. v. ANDREA ELECS. CORP. 7
Claim 6 recites:
The apparatus according to claim 5, wherein said
current minimum value is set to said future mini-
mum value periodically.
’345 patent, col. 9, ll. 65–67.
Claim 7 recites:
The apparatus according to claim 6, wherein said
future minimum value is replaced with the current
magnitude value when said future minimum value
is greater than said current magnitude value.
’345 patent, col. 10, ll. 1–4.
Claim 8 recites:
The apparatus according to claim 6, wherein said
current minimum value is replaced with the cur-
rent magnitude value when said current minimum
value is greater than said current magnitude
value.
’345 patent, col. 10, ll. 5–8.
Claim 9 recites:
The apparatus according to claim 5, wherein said
future minimum value is set to a current magni-
tude value periodically; said current-magnitude
value being the value of the magnitude of the cor-
responding frequency bin.
’345 patent, col. 10, ll. 9–12.
II. The Issues
A. The ’626 and ’627 IPR Proceedings
As noted, Apple filed its two IPR petitions—the ’626
IPR and the ’627 IPR—challenging claims 1–25 and 38–47
of the ’345 patent. Relevant to this appeal, Apple alleged
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8 APPLE INC. v. ANDREA ELECS. CORP.
that the challenged claims would have been anticipated or
obvious in light of three pieces of prior art.
In its ’626 IPR petition, Apple alleged that claims 6–9
of the ’345 patent would have been obvious over Hirsch and
Martin. Apple alleged in its ’627 IPR petition that claims
6–9 are anticipated by Helf or would have been obvious
over Helf and Martin. The Board instituted review on all
challenged claims and grounds raised in both petitions and
consolidated the two proceedings.
The three pieces of prior art are:
a. Rainer Martin, An Efficient Algorithm to Estimate the
Instantaneous SNR of Speech Signals (1993) (“Martin”)
Martin describes an algorithm for “instantaneous[ly]”
estimating the “signal-to-noise” ratio of speech signals.
J.A. 924. The Martin algorithm can be split into three ma-
jor parts: (1) computation of a smoothed short time power
estimate 𝑃𝑃�x(i) of signal x(i); (2) computation of the noise
power estimate Pn(i); and (3) computation of the estimated
signal-to-noise ratio of signal x(i) at time i, SNRx(i). J.A.
924–25. The algorithm tracks varying noise power levels
during speech activity over a defined number (“L”) of digi-
tal samples, wherein each set of L samples corresponds to
a portion of the signal, a “window,” e.g., 0.625 seconds. J.A.
925. Each window of length L is further divided into addi-
tional windows, or sub-windows (“W”). J.A. 925.
One important consideration of the algorithm is
whether the signal’s power is monotonically increasing for
a given period of time—that is, whether “the minimum
power of the last W windows . . . is monotonically increas-
ing” for that period of time. J.A. 925. Martin requires at
least two sub-windows (W ≥ 2) in order to determine
whether a signal’s power level is monotonically increasing.
J.A. 15. Under Martin’s approach, a scheme with no sub-
windows (i.e., W = 1) cannot be used to determine whether
the signal is monotonically increasing.
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APPLE INC. v. ANDREA ELECS. CORP. 9
b. H.G. Hirsch & C. Ehrlicher, Noise Estimation Tech-
niques for Robust Speech Recognition (1995) (“Hirsch”)
The Hirsch reference describes improvements to the
spectral subtraction process and provides algorithms for
estimating the noise level of an audio signal. J.A. 920–21.
Like the ’345 patent, one of the Hirsch algorithms utilize
an “adaptive threshold” for each frequency bin of the audio
signal to distinguish between noise and speech. Hirsch ex-
plains that one advantage of using an adaptive threshold
is that the methods estimate the noise levels “without an
explicit speech pause detection.” J.A. 920. Hirsch refers to
Martin as a “known” approach “to avoid the problem of
speech pause detection and to estimate the noise charac-
teristics just from a past segment of noisy speech.” J.A.
920, 923.
c. U.S. Patent No. 5,550,924 (“Helf”)
Helf describes a system for “reducing the background
noise of an input audio signal.” J.A. 964, col. 1, ll. 39–40.
Helf’s claimed system similarly utilizes Fourier transforms
to convert an audio signal into the frequency domain before
calculating the estimated noise in each frequency bin. J.A.
964, col. 1, ll. 54–61.
Helf has two approaches for estimating the background
noise in an audio signal: (1) a “stationary estimator” to
compute a noise estimate, “Bk”; and (2) a “running mini-
mum estimator” to compute a noise estimate “Mk.” Helf
explains that the first approach, the method utilizing a sta-
tionary estimator, is more accurate but requires one second
intervals of solely background noise. J.A. 966, col. 6, ll. 33–
39.
The second approach, the method utilizing a running
minimum estimator, is less accurate but develops back-
ground noise estimates in ten seconds under any condi-
tions. J.A. 966, col. 6, ll. 37–39. This approach calculates
the differences between the noise estimate, Mk, and
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10 APPLE INC. v. ANDREA ELECS. CORP.
previous background noise estimates according to a for-
mula. J.A. 967, col. 8, ll. 54–57. If the overall difference
exceeds a threshold, then Mk is used as the new back-
ground noise estimate. This approach will only occur if two
steps are met: (1) the noise estimates from the stationary
estimator have not been updated for more than ten sec-
onds; and (2) when the calculated value “D” of the Helf pa-
tent exceeds a particular threshold. J.A. 967, col. 8, ll. 33–
60.
1. The ’626 IPR
In its ’626 IPR petition, Apple argued that Martin dis-
closes the “current minimum” and “future minimum” limi-
tations required by claims 6–9. According to Apple,
Martin’s “noise floor estimation process” algorithm uses a
“current minimum,” Pn(i), and a “future minimum,” PMmin,
to track the minimum signal power, Px(i), during a prede-
termined period. Apple asserted that a person having or-
dinary skill in the art (a “POSA”) would have understood
that Martin’s algorithm could also be used to track the
“magnitude” of the noise signal, as required by claims 6–9
of the ’345 patent. As an example, Apple’s expert witness,
Dr. Hochwald, derived certain estimated noise floor values,
Pn(i), and minimum observed noise power values, PMmin, by
inputting certain variables. In this example, Dr. Hochwald
assumed that there are no sub-windows (W = 1). J.A. 130–
131.
In its Patent Owner Response, Andrea argued that
Martin does not disclose a “future minimum,” as required
by claims 6–9. In support of this position, Andrea ex-
plained that in both the “monotonically increasing” and the
“non-monotonically increasing” applications of the algo-
rithm, there is no future minimum and similarly utilized
an example of the algorithm to demonstrate its point. J.A.
280–91. Unlike Dr. Hochwald, however, Andrea’s expert
witness, Dr. Douglas, applied Martin’s algorithm in the
context of multiple sub-windows (W ≥ 2) because a
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APPLE INC. v. ANDREA ELECS. CORP. 11
determination of whether a signal’s power is monotonically
increasing over window length L requires at least two sub-
windows. J.A. 925.
Apple rebutted Andrea’s arguments on reply, respond-
ing that Andrea mischaracterized Martin and read non-ex-
istent limitations into the claims. First, Apple argued that
where Martin is configured to use one sub-window (W = 1),
it is not necessary to determine whether the sound is mon-
otonically increasing. J.A. 463. Therefore, when there is
only one sub-window, Martin discloses a future minimum
because the Pn(i) value (current minimum) is set to the
same PMmin value (future minimum), irrespective of which
update equation is used. J.A. 464.
Apple further argued that even under Andrea’s “multi-
ple-sub-windows” application of the algorithm, the Martin
algorithm still teaches a future minimum. J.A. 465–68.
Apple contended that the claims do not specify the period
over which the future minimum must be calculated, and as
a result, in a scenario where a signal is monotonically in-
creasing, Martin satisfies the claims. J.A. 467. Apple ar-
gued that in cases where a signal is not monotonically
increasing, the claims do not prohibit calculating the future
minimum over a particular data window or using the min-
imum of a previous sub-window as the “future minimum.”
Apple submitted a reply expert declaration to support
its analysis of the Martin algorithm in the context of mul-
tiple sub-windows. Andrea subsequently deposed Apple’s
expert witness for a second time but did not request au-
thorization to file a sur-reply or move to strike any portion
of Apple’s reply briefing. J.A. 252.
During oral argument, the Board questioned whether
Apple’s reply raised new arguments that were not other-
wise discussed in the petition. J.A. 536–38 (13:5–15:18).
In response, Apple pointed to the two pages in its petition
addressing how the Martin algorithm teaches a noise floor
estimation process that uses a “current minimum” and a
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12 APPLE INC. v. ANDREA ELECS. CORP.
“future minimum” to track the minimum signal power dur-
ing a predetermined period. J.A. 537 (14:3–21), J.A. 128–
29.
2. The ’627 IPR
In its ’627 IPR petition, Apple argued that Helf dis-
closes the “periodically” limitation of claims 6–9. Claims
6–9 recite a current and future minimum, wherein the two
values are set “periodically.” In proposing a construction
for the term, Apple relied on a definition provided by Web-
ster’s Dictionary that defined “periodically” as “1: at regu-
lar intervals of time” and “2: from time to time.” J.A. 2483.
Apple took the position that both of these definitions apply
to the term “periodically” in the context of the ’345 patent.
With respect to its anticipation and obviousness argu-
ments, Apple stated that Helf discloses a current minimum
and future minimum that is set “periodically,” or “from
time to time.” Reasoning that Helf’s running minimum es-
timator sets the background noise estimate, Nk, (current
minimum) to the running minimum estimate, Mk, (future
minimum) whenever the difference between these values
exceeds a threshold, Apple argued that this setting occurs
“periodically,” or “from time to time.” J.A. 2483.
Alternatively, Apple contended that Helf discloses the
“periodically” limitation because, in cases where the sta-
tionary estimator approach is not available (e.g., the audio
signal continuously contains speech without any pauses),
the current background noise estimate approach is set to
the minimum estimate, Mk, 10 seconds after the system
starts. J.A. 2483. Apple also argued that a POSA would
have modified Helf’s system, in light of Martin, to update
the current and future minimum values “at regular inter-
vals of time.” Appellant Br. 62–63.
In response, Andrea argued that the term “periodi-
cally” should only be construed as “occurring at regular in-
tervals of time,” and not “from time to time.” J.A. 2614. In
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APPLE INC. v. ANDREA ELECS. CORP. 13
support of its position, Andrea explained that the ’345 pa-
tent written description’s use of the term is only consistent
with the first definition of “periodically.” J.A. 2615. For
example, the written description only references the term
once, when describing an embodiment of the invention,
wherein “[t]he future and current minimum values are cal-
culated continuously and initiated periodically, for exam-
ple, every 5 seconds as determined in step 724 and control
is advanced to steps 722 and 726 wherein the new future
and current minimum are calculated.” ’345 patent, col. 8
ll.36–40.
Based on its proposed construction of “periodically,”
Andrea argued that Helf does not disclose the “periodi-
cally” limitation because Helf’s running minimum estima-
tor does not set the current background noise estimate to
the minimum estimate Mk at regular intervals of time. See
J.A. 2632.
3. The Board’s Final Written Decisions
In its Final Written Decisions for the ’626 and ’627
IPRs, the Board concluded that Apple had demonstrated
that claims 1–5, 10–25, and 38–47 of the ’345 patent are
unpatentable. The Board held, however, that in neither of
the two IPRs had Apple demonstrated that claims 6–9 of
the ’345 patent are unpatentable.
With respect to the ’626 IPR, the Board concluded that
a POSA would not have found it obvious to modify Hirsch’s
system, based on a scenario from Martin where there are
no sub-windows (W = 1). Importantly, the Board refused to
consider Apple’s responsive arguments in its reply where it
considered the Martin algorithm with multiple sub-win-
dows (W ≥ 2), finding that these arguments raised a new
theory of unpatentability for the first time in its reply brief.
With respect to the ’627 IPR, the Board adopted An-
drea’s proposed claim construction for “periodically” and
construed the term to mean “at regular intervals of time.”
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14 APPLE INC. v. ANDREA ELECS. CORP.
Based on this construction, the Board concluded that Apple
failed to prove that Helf, alone or in combination with Mar-
tin, discloses the “periodically” limitation as required by
claims 6–9 of the ’345 patent.
III. DISCUSSION
A. Was the Board Correct When It Determined That Ap-
ple’s Reply Brief in the ’626 IPR Raised a New Theory of
Unpatentability?
The Board’s determinations that a party exceeded the
scope of a proper reply are reviewed for abuse of discretion.
See Ericsson Inc. v. Intellectual Ventures I LLC, 901 F.3d
1374, 1379 (Fed. Cir. 2018); Intelligent Bio-Sys., Inc. v. Il-
lumina Cambridge Ltd., 821 F.3d 1359 (Fed. Cir. 2016).
Apple contends that the Board abused its discretion by re-
fusing to consider arguments and evidence that Apple ad-
vanced in its ’626 IPR reply brief.
“It is of the utmost importance that petitioners in the
IPR proceedings adhere to the requirement that the initial
petition identify ‘with particularity’ the ‘evidence that sup-
ports the grounds for the challenge to each claim.’” See In-
telligent Bio-Sys., 821 F.3d at 1369 (citing 35 U.S.C.
§ 312(a)(3)). And “[a] reply may only respond to arguments
raised in the corresponding opposition, patent owner pre-
liminary response, or patent owner response.” 37 C.F.R.
§ 42.23(b). Therefore, in determining whether Apple ap-
propriately advanced its arguments regarding the applica-
tion of the Martin algorithm with multiple sub-windows
(W ≥ 2), we must consider: whether the petitioner’s reply
brief is responsive to arguments originally raised in its pe-
tition; or whether the reply arguments are responsive to
arguments raised in the patent owner’s response brief.
Andrea contends that the Board correctly precluded
Apple’s arguments applying the Martin algorithm with
multiple sub-windows because Apple’s ’626 IPR petition
was “intentionally” premised on a scenario in which there
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APPLE INC. v. ANDREA ELECS. CORP. 15
were no sub-windows (W = 1). Andrea argues that Apple’s
multiple sub-window discussion is a “new theory of un-
patentability,” particularly because the accompanying ex-
pert declaration to Apple’s petition relied solely upon a
scenario wherein W = 1.
We disagree. Apple’s legal ground did not change in its
reply—its reply still asserted that claims 6–9 would have
been obvious over Hirsch and Martin. Moreover, Apple’s
reply relies on the same algorithm from the same prior art
reference to support the same legal argument: that Martin
discloses the “current minimum” and “future minimum”
limitations of the asserted claims.
Indeed, Apple’s reply arguments regarding Martin are
not the types of arguments that we have previously found
to raise a “new theory of unpatentability.” For example, in
Ariosa Diagnostics v. Verinata Health, Inc., the Board re-
jected the petitioner’s reliance on its reply submissions be-
cause the petitioner discussed “previously unidentified
portions of a prior-art reference to make a meaningfully
distinct contention.” 805 F.3d 1359, 1367 (Fed. Cir. 2015).
The reply declaration pointed to an embodiment of the
prior art that was not discussed in the petition. Id. Ac-
cordingly, we held that the Board reasonably determined
that the reply declaration raised a new argument that was
not otherwise addressed in the petition.
Similarly, in Intelligent Bio-Systems, we concluded
that the reply brief and accompanying declaration ex-
ceeded the scope of the petition when the petitioner cited
several new non-patent literature references and argued
that a POSA would have considered the claim obvious for
reasons other than those described in the originally relied-
upon prior art. 821 F.3d at 1369.
Unlike the above cases, Apple’s reply does not cite any
new evidence or “unidentified portions” of the Martin ref-
erence. Apple’s reply brief merely demonstrates another
example of the same algorithm to further explain why
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16 APPLE INC. v. ANDREA ELECS. CORP.
Martin discloses the “current minimum” and “future mini-
mum” limitations of claims 6–9. The Board “pars[es] [the
petitioner’s] arguments on reply with too fine of a filter.”
See Ericsson Inc., 901 F.3d at 1380. It is unreasonable to
hold petitioners to such a high standard that, if they choose
to rely on one example of an algorithm, they must either
discuss all potential permutations of the variables or risk
waiving the opportunity to further discuss other relevant
examples in their reply. Chamberlain Grp., Inc. v. One
World Techs., Inc., 944 F.3d 919, 925 (Fed. Cir. 2019) (“Par-
ties are not barred from elaborating on their arguments on
issues previously raised.”).
Further, any ambiguity as to whether Apple raised a
new argument on reply is eliminated when we consider
whether Apple’s reply arguments are responsive to argu-
ments raised in Andrea’s Patent Owner Response. 1 As we
have regularly held, “the petitioner in an inter partes re-
view proceeding may introduce new evidence after the pe-
tition stage if the evidence is a legitimate reply to evidence
introduced by the patent owner.” Anacor Pharm., Inc. v.
Iancu, 889 F.3d 1372, 1380–81 (Fed. Cir. 2018).
In its opposition, Andrea argued that Apple’s argument
is inherently flawed because Martin requires at least two
sub-windows in order to perform one step of the algorithm.
Andrea’s response brief devoted at least seven pages to its
discussion about why the Martin algorithm, in the context
of multiple sub-windows, does not disclose a “future mini-
mum.” J.A. 287–293. Apple’s reply squarely responds to
Andrea’s Patent Owner Response. In addition to rebutting
Andrea’s arguments addressing the W = 1 scenario, Apple
argued that Andrea’s multiple sub-window discussion
1 Notably, neither the Board nor Andrea addressed
whether Apple’s reply arguments are responsive to those
arguments raised in Andrea’s Patent Owner response. J.A.
15; Appellee Br. 50–65.
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APPLE INC. v. ANDREA ELECS. CORP. 17
“reads non-existent limitations into the claims” and why
the algorithm, even in the context of multiple sub-windows,
discloses a “future minimum.” J.A. 465–68.
Stepping back a bit of distance persuades us that the
Board’s decision to ignore Apple’s responsive arguments to
issues raised by Andrea in its Patent Owner Response is
not supported as a matter of law; the conclusion that the
reply brief constitutes an impermissible new matter is an
abuse of discretion.
B. Would a POSA Have Understood the Claim Term “Pe-
riodically” to Mean “At Regular Intervals of Time”?
The Court reviews the construction of a claim term by
the Board without deference. Teva Pharm. USA, Inc. v.
Sandoz, Inc., 574 U.S. 318, 332–33 (2015). Subsidiary fac-
tual findings are reviewed for substantial evidence.
Knowles Elecs. LLC v. Iancu, 886 F.3d 1369, 1374 (Fed. Cir.
2018). When this court reviews the claim construction of a
patent claim term in an IPR appeal after the patent has
expired, such as in this case, we apply the standard estab-
lished in Phillips, not the “broadest reasonable interpreta-
tion.” See In re CSB-System Int’l, Inc., 832 F.3d 1335, 1342
(Fed. Cir. 2016); Microsoft Corp. v. Enfish, LLC, 662 F.
App’x 981, 984 (Fed. Cir. 2016).
Apple argues that, with respect to the ’627 IPR, the
Board erred because it did not construe “periodically” to
also mean “from time to time.” Appellant Br. 51.
We disagree. The written description’s only use of the
term “periodically” supports the Board’s construction. The
written description recites: “The future and current mini-
mum values are calculated continuously and initiated pe-
riodically, for example, every 5 seconds as determined in
step 724 and control is advanced to steps 722 and 726
wherein the new future and current minimum are calcu-
lated.” ’345 patent, col. 8, ll. 36–38 (emphases added). The
written description affirmatively illustrates calculating the
Case: 18-2382 Document: 45 Page: 18 Filed: 02/07/2020
18 APPLE INC. v. ANDREA ELECS. CORP.
future and current minimum values “every 5 seconds” or
within a “regular interval of time.” ’345 patent, col. 8, ll.
36–38.
We recognize that preferred embodiments do not act as
claim limitations, but when the invention as claimed covers
only the preferred embodiment described in the written de-
scription, it is questionable whether a patentee may assert
a proposed construction that is broader than the plain lan-
guage of the claim. See Phonometrics, Inc. v. N. Telecom
Inc., 133 F.3d 1459, 1466 (Fed. Cir. 1998) (“Although
claims are not necessarily restricted in scope to what is
shown in a preferred embodiment, neither are the specifics
of the preferred embodiment irrelevant to the correct
meaning of claim limitations.”). Here, the written descrip-
tion’s only reference to “periodically” supports the Board’s
conclusion that a POSA would have understood this term
to mean “at regular intervals of time” rather than “from
time to time.”
Apple also argues that the “periodically” term should
be construed to mean “from time to time” because the ’345
patent discloses setting the future minimum value to a cur-
rent magnitude value whenever “the smoothed estimate [of
the current magnitude Y(n)] is less than the calculated fu-
ture minimum value.” Appellant Br. 51–52 (citing ’345 pa-
tent, col. 8, ll. 36–40). Apple contends that this “smoothed
estimate” update is an example of setting the minimum
values “from time to time,” and argues that in order “to be
consistent” with the intrinsic evidence, “periodically” must
be construed to encompass both ways of updating the val-
ues. Apple asserts that to adopt the Board’s limited con-
struction would affirm “a claim construction that excludes
the preferred embodiment.” Reply Br. 7.
This argument is unconvincing. Even assuming that
the ’345 patent addresses different ways of setting the fu-
ture and current minimum values, Apple conflates the
written description’s disclosures of two different methods
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APPLE INC. v. ANDREA ELECS. CORP. 19
of setting minimum values with the separate limitation of
setting these values on a periodic basis. In fact, claims 6–
9 of the ’345 patent do not capture the “smoothed estimate
value” method described in the ’345 patent—nor do they
need to.
As we have held, “[when] the patent describes multiple
embodiments, every claim does not need to cover every em-
bodiment. This is particularly true [when] the plain lan-
guage of a limitation of the claim does not appear to cover
that embodiment.” Pacing Techs., LLC v. Garmin Int’l,
Inc., 778 F.3d 1021, 1026 (Fed. Cir. 2015) (internal cita-
tions omitted). The plain language of the claims-at-issue
does not cover the “smoothed estimate” method. Rather,
other claims, such as claims 23, 36, and 45 of the ’345 pa-
tent, which do not include the “periodically” term, discuss
a method of determining future minimum values based on
“the step of smoothing the estimate of each frequency bin.”
See, e.g., ’345 patent, col. 12, ll. 4–54. We decline to extend
the scope of the “periodically” term beyond the plain text of
the intrinsic record.
Nor does the extrinsic evidence help Apple’s position.
The Board relied on the testimony of Dr. Douglas, Andrea’s
expert witness, who opined that the Board’s construction is
the “only . . . definition . . . consistent with the specification
of the ’345 patent and its use in the particular field of audio
signal processing.” J.A. 33. Specifically, Dr. Douglas ex-
plained that the “period” of an audio signal is the amount
of time it takes for a signal to repeat, and that this amount
of time occurs at regular intervals. Id.
Moreover, Apple’s expert witness admitted during his
deposition that, “out of the context of the ’345 [patent],” the
definition of “periodically” is “at regular time intervals.”
J.A. 33. When asked what he perceived “periodically” to
mean in the context of the ’345 patent written description,
Apple’s expert simply responded that “all I can do is read
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20 APPLE INC. v. ANDREA ELECS. CORP.
what it says,” which is “that “[i]t’s doing something period-
ically, for example, every five seconds.” Id.
We have regularly held that extrinsic evidence in the
form of expert testimony can “provide background on the
technology at issue” and “ensure that the court’s under-
standing of the technical aspects of the patent is consistent
with that of a person of skill in the art, or to establish that
a particular term in the patent or the prior art has a par-
ticular meaning in the pertinent field.” Phillips v. AWH
Corp., 415 F.3d 1303, 1318 (Fed. Cir. 2005). Here both par-
ties’ experts offered testimony in favor of the Board’s con-
struction of “periodically” as limited to “at regular intervals
of time.” We find that the Board’s subsidiary factual find-
ings with respect to how a person skilled in the art would
have understood the “periodically” limitation are sup-
ported by substantial evidence. Knowles Elecs., 886 F.3d
at 1374.
Accordingly, because the ’345 patent’s written descrip-
tion and the claim language support a construction of “pe-
riodically” as “at regular intervals of time” and not “from
time to time,” and because there is substantial evidence
that a person skilled in the art would have understood the
term to be limited to “at regular intervals of time,” we con-
clude that the Board did not err in its construction of the
“periodically” term.
C. In the ’627 IPR Proceedings, Did Apple Satisfy Its
Burden of Proving That Claims 6–9 of the ’345 Patent Are
Anticipated or Would Have Been Obvious?
Apple argues that, even under the Board’s construction
of “periodically,” the Board erred in its ’627 IPR finding
that Apple failed to prove that claims 6–9 are anticipated
or would have been obvious.
We disagree. With respect to its anticipation argu-
ment, Apple asserts that Helf discloses the “periodically”
limitation because its running minimum estimator sets the
Case: 18-2382 Document: 45 Page: 21 Filed: 02/07/2020
APPLE INC. v. ANDREA ELECS. CORP. 21
background noise estimate, Nk, to the minimum estimate,
Mk, at regular intervals of time. Appellant Br. 58. But sub-
stantial evidence supports the Board’s findings that Helf’s
running minimum estimator does not meet the “periodi-
cally” limitation. See Nobel Biocare Servs. AG v. Instradent
USA, Inc., 903 F.3d 1365, 1375 (Fed. Cir. 2018) (“Anticipa-
tion is a question of fact that we review for substantial ev-
idence.”).
As described above, Helf discloses two approaches for
estimating the background noise in an audio signal: (1) a
stationary estimator method; and (2) a running minimum
estimator method. Helf’s running minimum estimator
method is a “back-up” approach. That is, the Helf system
does not employ the running minimum estimator method
unless the system cannot employ the stationary estimator
approach. J.A. 966, col. 6, ll. 33–39. Helf explains that the
system is set up in this configuration because the station-
ary minimum estimator is “more accurate,” but requires
one second intervals of solely background noise. J.A. 966,
col. 6, ll. 35–39.
Accordingly, the system employs a “running minimum
estimator” in the alternative, which is less accurate but de-
velops background noise estimates in ten seconds “under
any conditions.” J.A. 966, col. 6, ll. 37–39. The background
noise estimate update will not occur unless other condi-
tions are met, such as when an algorithm determines that
the difference between Mk and the past background noise
estimate exceeds a certain threshold. J.A. 967, col. 8, ll.
10–60.
Under this configuration, Helf cannot satisfy the “peri-
odically” limitation because it does not update the noise es-
timate Mk or Nk, which Apple alleges is the “current
minimum,” at regular intervals of time. The running min-
imum estimator approach only updates the background
Case: 18-2382 Document: 45 Page: 22 Filed: 02/07/2020
22 APPLE INC. v. ANDREA ELECS. CORP.
noise estimate if the stationary estimator approach is una-
vailable and if certain conditions are met.
In response, Apple argues that in situations where only
the running minimum estimator can operate, the back-
ground noise estimate, Nk, is set to the minimum estimate,
Mk, “10 seconds after the system starts.” Appellant Br. 58
(citing J.A. 967, col. 8, ll. 33–43). Apple contends that the
update that occurs “10 seconds after the system starts” oc-
curs “periodically.” Appellant Br. 58. But this update does
not occur “at a regular interval.” It occurs once, after the
running minimum estimator is activated.
Although Apple insists that the “periodically” limita-
tion also may be met if the Helf system is “power-cycled on
and off,” Reply Br. 26, such an argument is unavailing. Not
only does the suggestion of “power-cycling” the system de-
feat the purpose of the “periodically” limitation, but it also
requires a user to power-cycle the Helf system at regular
intervals because any delay would modify the amount of
time between each background noise estimate update. We
decline to read such a strained interpretation of the prior
art so as to obviate the claimed limitation.
Similarly, we find that the Board did not err in its con-
clusion that Helf, in combination with Martin, does not dis-
close the “periodically” limitation. Apple asks us to
overrule the Board’s fact-intensive inquiry as to whether a
person skilled in the art would have been motivated to com-
bine Helf and Martin to develop a system that updates the
current and future minimum values “at regular intervals.”
We decline that invitation. Corning v. Fast Felt Corp., 873
F.3d 896, 902 (Fed. Cir. 2017).
Substantial evidence supports the Board’s finding, par-
ticularly when Dr. Hochwald’s testimony on the motivation
to combine issue consisted of one paragraph of conclusory
statements. See J.A. 2935–36.
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APPLE INC. v. ANDREA ELECS. CORP. 23
Having determined that substantial evidence supports
the Board’s finding that a person skilled in the art would
not have been motivated to combine Martin with Helf so as
to modify the running minimum estimator by adding up-
dates to the background noise estimate, Nk, and the run-
ning minimum estimate, Mk, “every ten seconds during
operation of the running minimum estimator,” we conclude
that Helf, in combination with Martin, does not render ob-
vious the “periodically” limitation, as required by claims 6–
9 of the ’345 patent. 2
IV. CONCLUSION
For the reasons stated above, we vacate the Board’s
findings in the ’626 IPR and remand for consideration of
the arguments raised by Apple in its ’626 IPR reply brief.
We affirm the Board’s findings in the ’627 IPR.
AFFIRMED-IN-PART, VACATED-IN-PART, AND
REMANDED
2 Apple also argues that the Board’s rejection of Ap-
ple’s proposed modification for Helf, in light of Martin, only
relates to claim 6 and not claim 9 because claim 9 specifies
updates to the “future minimum value” (as opposed to up-
dates to the “current minimum value”). Appellant Br. 64;
Reply Br. 31. Apple misunderstands the Board’s reason-
ing. The Board concluded that a person skilled in the art
would not have modified the “running minimum estimator”
to update at regular ten second intervals—such a conclu-
sion applies equally to both the background noise estimate
and running minimum estimate Mk that are set by the run-
ning minimum estimator. J.A. 47–48.
Apple Inc. v. Andrea Electronics Corporation
Combined Opinion