United States Court of Appeals
      for the Federal Circuit
                ______________________

    TELEFONAKTIEBOLAGET LM ERICSSON,
                Appellant

                           v.

   TCL CORPORATION, TCL COMMUNICATION
    TECHNOLOGY HOLDINGS LIMITED, TCT
    MOBILE LIMITED, TCT MOBILE, INC., TCT
              MOBILE (US) INC.,
                    Appellees
             ______________________

                 2017-2381, 2017-2385
                ______________________

    Appeals from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in Nos. IPR2015-
01584, IPR2015-01600.
                 ______________________

              Decided: November 7, 2019
               ______________________

    DEBRA JANECE MCCOMAS, Haynes & Boone, LLP, Dal-
las, TX, argued for appellant. Also represented by J.
ANDREW LOWES, CLINT S. WILKINS, Richardson, TX.

    JULIE S. GOLDEMBERG, Morgan, Lewis & Bockius LLP,
Philadelphia, PA, argued for appellees. Also represented
by WILLIAM R. PETERSON, Houston, TX; NATHAN W.
MCCUTCHEON, BRADFORD CANGRO, Washington, DC.
                ______________________
2       TELEFONAKTIEBOLAGET LM ERICSSON v. TCL CORPORATION




Before NEWMAN, LOURIE, and CLEVENGER, Circuit Judges.
NEWMAN, Circuit Judge.
    Telefonaktiebolaget LM Ericsson (“Ericsson”) is the
owner of United States Patent No. 6,029,052 (“the ’052 pa-
tent”). TCL Corporation, TCL Communication Technology
Holdings, Ltd., TCT Mobile Limited, TCT Mobile Inc., and
TCT Mobile (US), Inc., (collectively “TCL”) filed two peti-
tions for inter partes review (“IPR”) of claims 13, 15, 16,
and 18 of the ’052 patent. The Patent Trial and Appeal
Board (“PTAB” or “Board”) instituted review, consolidated
the petitions, and ruled that all of the challenged claims
are unpatentable on the ground of obviousness. 1
    The ’052 patent describes and claims a “direct conver-
sion receiver” for wireless communication systems that
may receive signals from systems that operate at different
frequency bands. The primary issue on appeal is whether
a specific foreign publication is an available reference
against the ’052 patent. We affirm the Board’s decision
that the specified publication is an available reference, and
based on this publication in combination with other prior
art we affirm the Board’s decision of invalidity of the chal-
lenged claim.
                 The Ericsson ’052 Patent
    The method claimed in the ’052 patent is stated to be
an improvement over conventional modes of receiving and
processing wireless signals from communication systems
that operate at differing frequencies. Such systems previ-
ously required separate receiver components to process sig-
nals arriving at differing frequencies. The ’052 patent
claims a method whereby receivers “can receive signals at



    1   TCL Corp. v. Telefonaktiebolaget LM Ericsson,
IPR2015-01584 and IPR2015-01600, 

,
(P.T.A.B. Jan. 24, 2017) (“Board Op.”).
TELEFONAKTIEBOLAGET LM ERICSSON v. TCL CORPORATION          3



multiple frequency bands without requiring significant
hardware duplication.” ’052 patent, col. 2, ll. 3–28.
    Claim 18 is at issue on appeal, shown with claim 13
from which it depends:
       13. A method for receiving a communication
   signal, comprising the steps of:
       receiving a communication signal in any one of
   a plurality of frequency bands, the communication
   signal having a bandwidth;
       band-pass filtering the received communica-
   tion signal;
       amplifying the band-pass filtered signal;
       mixing the band-pass filtered signal with in-
   phase and quadrature oscillator signals to generate
   an in-phase and a quadrature received signal; and
       low pass filtering the in-phase received signal
   and the quadrature received signal in a low pass
   in-phase filter and a low pass quadrature filter, re-
   spectively,
       wherein direct conversion is used for convert-
   ing all received communication signals in any one
   of the plurality of frequency bands.
       18. The method of claim 13, further comprising
   the steps of generating a first oscillator signal and
   frequency-dividing the first oscillator signal to gen-
   erate the in-phase and quadrature oscillator sig-
   nals prior to the step of mixing.
Patent Figure 3 depicts the method of the ’052 patent:
4       TELEFONAKTIEBOLAGET LM ERICSSON v. TCL CORPORATION




The specification explains that wireless signals are re-
ceived at antenna 10, and bandsplitter 30 splits the signals
into two frequency bands. The split signals are filtered by
band pass filters (BPF), shown at 12a and 12b, to remove
out-of-band unwanted components that are frequency band
specific. The filtered signals are amplified by low-noise
amplifiers (LNA) shown at 34a and 34b. The signals pro-
ceed to a mixing circuit that includes a voltage-controlled
oscillator (VCO) 36 for generating an oscillator signal. A
quadrature 2 generator 38 separates the oscillator signal
into in-phase (I) and quadrature (Q) components.
     Frequency phase shifting is conducted by either the
quadrature generator 38 or a frequency divider that gener-
ates quadrature local oscillator signals. The phase shifter
receives the signal from a local oscillator and outputs two
signals separated by 90 degrees. These divided signals are
sent to mixers 40 and 41, which compare the divided sig-
nals against the received signal. The signals are filtered in
an in-phase low pass filter 42a and a quadrature low pass
filter 42b, and the filtered signals are passed to conven-
tional baseband processing circuitry. ’052 patent, col. 3, ll.
9–28; col. 4, ll. 10–23.




    2     “Quadrature” means 90 degrees out of phase.
TELEFONAKTIEBOLAGET LM ERICSSON v. TCL CORPORATION        5



    The principal reference presented by petitioner TCL
and relied on by the PTAB is an article entitled “Multi-
modale Funktelefone” (translation: Multimodal Wireless
Telephones), authored by Professor Hans-Joachim
Jentschel et al. and published in the German technical
journal “Ingenieur der Kommunikationstechnik” (transla-
tion: Engineer of Communications Technology). The initial
question is whether this article is available as prior art.
                             I
                 The Jentschel Article
    Ericsson argues that the Jentschel article is not prior
art because it was not publicly available more than one
year before Ericsson’s earliest asserted filing date, and
thus is subject to antedating by Ericsson’s invention date.
Ericsson alternatively argues that even if Jentschel is
deemed to be prior art, the challenged claim is not obvious
in view thereof.
               A. Date of the Reference
    The Jentschel article was published in a German peri-
odical whose cover states the date “Mai/Juni” 1996, as fol-
lows:




J.A. 2377. May/June 1996 is more than one year earlier
than Ericsson’s filing date of July 1, 1997. However, it was
6    TELEFONAKTIEBOLAGET LM ERICSSON v. TCL CORPORATION




shown that this journal issue did not reach the UCLA li-
brary until October 1996. Ericsson argued that “Dates
alone on a document are insufficient as a matter of law to
establish public accessibility.” Patent Owner’s Response at
13.
     TCL sought to provide evidence of the date of availabil-
ity of this journal issue in university libraries in Germany.
On October 8, 2015 TCL submitted to the PTAB a letter
from a librarian who was described as a member of the “Pe-
riodicals Team” at the Technische Informationsbibliothek
and Universitätsbibliothek in Hannover, Germany. The
letter stated that the public had library access to the
May/June 1996 issue on June 19, 1996. On March 1, 2016,
Ericsson objected to the letter as inadmissible hearsay.
This statement was withdrawn when the librarian declined
to provide a sworn statement and declined to testify in the
United States.
     On July 18, 2016, TCL moved to submit the sworn Dec-
laration of Doris Michel, a librarian at the Technische Uni-
versität Darmstadt in Germany. Ericsson objected, stating
that the submission was not in compliance with the Board’s
Rules. The Rules require a petitioner to present sufficient
evidence, at the petition stage, to inform the patent owner
of the issues to be presented, and PTO regulation 37 C.F.R.
§ 42.123(b) requires that a party who seeks to submit new
or supplemental information more than one month after
the date an IPR is instituted
    must show why the supplemental information rea-
    sonably could not have been obtained earlier, and
    that consideration of the supplemental information
    would be in the interests-of-justice.
Ericsson states that TCL was not diligent in providing ad-
missible information because TCL did not start to look for
this declarant until after Ericsson filed its objections to the
Jentschel article.
TELEFONAKTIEBOLAGET LM ERICSSON v. TCL CORPORATION          7



    The Board held that the Michel Declaration met the
regulatory standard, based on TCL’s recitation of its diffi-
culties in finding a witness with personal knowledge of
these past events. TCL stated that “Doris Michel is the
only individual TCL found who has personal knowledge of
the record-keeping procedures used in 1996, was willing to
sign a sworn declaration, and is willing to travel to the
U.S. to be deposed.” Mot. to File Suppl. Info., at 5 (empha-
ses original).
    Ericsson argues that the time consumed by searching
for a witness does not meet the regulatory standard, citing
Ultratec, Inc. v. CaptionCall, LLC, 

, 1272
(Fed. Cir. 2017) as holding that the standard for determin-
ing that evidence could not have been provided earlier re-
quires showing that the evidence did not exist earlier.
Ericsson states that the Board improperly allowed TCL to
submit tardy evidence to attempt to establish the publica-
tion date, and that Ericsson was prejudiced by this delay,
for it had been developing its defense against references
that the Board discarded after it accepted Jentschel as the
principal reference. Ericsson also states that due to the
delay it lost the opportunity to amend its claims.
     TCL responds that Regulation § 42.123(b) gives the
Board discretion to accept a tardy submission and to con-
sider the interest of justice. TCL argues that the Jentschel
article is very close prior art and that Ericsson was allowed
to file supplemental briefing and to depose Ms. Michel.
    Our review of the Board’s action is on the abuse of dis-
cretion standard. The Board stated that “consideration of
the supplemental information would be in the interests of
justice,” granting the motion. Mot. to File Suppl. Info. Dec.,
at 8. The Board recognized the possible burden on Erics-
son, and assured that Ericsson had the opportunity to de-
pose Ms. Michel and to respond to the substance of the
Jentschel reference.
8    TELEFONAKTIEBOLAGET LM ERICSSON v. TCL CORPORATION




    We conclude that the Board did not abuse its discretion
in admitting the Michel Declaration, for when the chal-
lenged evidence is reasonably viewed as material, and the
opponent has adequate opportunity to respond and to pro-
duce contrary evidence, the interest of justice weighs on the
side of admitting the evidence. Cf. Genzyme Therapeutic
Prods. Ltd. P’ship v. Biomarin Pharm. Inc., 

,
1366 (Fed. Cir. 2016) (“[T]he introduction of new evidence
in the course of the [PTAB] trial is to be expected in inter
partes review trial proceedings and, as long as the opposing
party is given notice of the evidence and an opportunity to
respond to it, the introduction of such evidence is perfectly
permissible under the APA.”).
 B. Public Accessibility of the Jentschel Reference
     Ericsson argues that the date of availability to the pub-
lic of the Jentschel reference was not established by the
Michel Declaration, even if that Declaration is deemed ad-
missible. A reference is deemed publicly available if it has
been “disseminated or otherwise made available to the ex-
tent that persons interested and ordinarily skilled in the
subject matter or art, exercising reasonable diligence, can
locate it.” Jazz Pharm., Inc. v. Amneal Pharm., LLC,

, 1355 (Fed. Cir. 2018). “Because there are
many ways in which a reference may be disseminated to
the interested public, ‘public accessibility’ has been called
the touchstone in determining whether a reference consti-
tutes a ‘printed publication’ . . . .” In re Hall, 

,
898–99 (Fed. Cir. 1986). Whether a reference is publicly
accessible is a question of fact. In re NTP, Inc., 

, 1296 (Fed. Cir. 2011).
    The librarian Doris Michel declared that the journal
Ingenieur der Kommunikationstechnik was in the collec-
tion of the Darmstadt Library “since Volume 13, which cor-
responds to the year 1963.” Board Op. at *6 (quoting
Michel Decl. (translation) at 3). She declared that she
worked at this Library in 1996, that Library records show
TELEFONAKTIEBOLAGET LM ERICSSON v. TCL CORPORATION          9



that the journal issue dated Mai/Juni 1996 was catalogued
and shelved with the shelf call number Tech Z Fe 57, and
the Mai/Juni 1996 issue that she now obtained from the
Library bears such call number. Michel Decl. at 4. She
declared that this issue “was inventoried by the Library on
June 18, 1996 [and] was openly accessible for use to the
public after a processing time of 1-2 days.” Michel Decl.
at 4.
     Doris Michel declared that her testimony was based on
her review of the Library register, her personal knowledge
of the Library’s registration practices, and the current con-
dition of the Mai/Juni 1996 issue that was in the Library.
Michel Decl. at 3. She provided copies of the index card
(“Kardex sheet”) that recorded the Library’s accession of
this journal and showed the Library’s entry for the issue
identified as “Tech Z Fe 57;” she stated that this entry
matches the sticker on the Library’s copy of the Mai/Juni
1996 issue. Michel Decl. at 4, 6. She also testified that the
Kardex sheet itself was not publicly available. Michel Decl.
at 4. The lack of public availability of the Kardex sheet was
not shown to impede public access to the Jentschel refer-
ence after a processing time of 1-2 days.
    The Board found as fact that the Jentschel article was
received and shelved in the Darmstadt library in May/June
1996. The Board reasoned that “Here, the periodical issue
was housed in a library accessible to the public, published
in a periodical that had been published for more than thirty
years, and presumably articles within an issue were
treated as a public disclosure of information.” Board Op.
at *6. See also Blue Calypso, LLC v. Groupon, Inc., 

, 1348 (Fed. Cir. 2016) (the criterion is whether
the publication was publicly available “to the extent that
persons interested and ordinarily skilled in the subject
matter or art exercising reasonable diligence, can locate it”)
(quoting Kyocera Wireless Corp. v. Int’l Trade Comm’n, 

, 1350 (Fed. Cir. 2008)).
10   TELEFONAKTIEBOLAGET LM ERICSSON v. TCL CORPORATION




    Ericsson argues that “precedent requires something
more than simply shelving the document in a library.” Re-
ply Br. 2. Ericsson argues that the only evidence of public
availability is the Kardex sheet of the Darmstadt Library,
and that this is insufficient support for the Board’s ruling
that the Jentschel article was publicly accessible in
May/June 1996. TCL responds that the Michel Declaration
constituted substantial evidence of public availability in
the Darmstadt Library.
    Ericsson states that the Board improperly placed on
Ericsson the burden of proving the date of availability of
the Jentschel article. Ericsson is correct that it did not bear
the ultimate burden of proof, for the proponent of a foreign
publication bears the burden of proving its availability if
challenged. However, Ericsson provided no evidence to
counter the Michel Declaration, the date on the face of the
journal, and the Library’s records showing receipt of the
journal and its shelving.
    This case is unlike cases in which a single dissertation
or thesis was housed in a library, e.g., In re Bayer, 

(CCPA 1978) (applicant’s uncatalogued, unshelved
master’s thesis was not publicly accessible); In re Cronyn,

, 1161 (Fed. Cir. 1989) (student undergradu-
ate theses were not publicly accessible because “they had
not been either cataloged or indexed in a meaningful way”).
     Ericsson does not dispute that this journal had been
published for at least thirty years and that the library was
accessible to the public. See GoPro, Inc. v. Contour IP
Holding LLC, 

, 693–95 (Fed. Cir. 2018)
(“[I]nterested members of the relevant public could obtain
the information if they wanted to.”). Cf. Voter Verified, Inc.
v. Premier Election Sols., Inc., 

, 1380 (Fed.
Cir. 2012) (the reference was available on-line and alt-
hough not meaningfully indexed it was publicly accessible
because the publication was well known to persons inter-
ested in the subject matter).
TELEFONAKTIEBOLAGET LM ERICSSON v. TCL CORPORATION       11



    Substantial evidence supports the Board’s ruling that
Jentschel was accessible to the public in the May/June
1996 period. The Board did not abuse its discretion in re-
ceiving the Jentschel article as a reference.
                            II
                      Obviousness
    We give plenary review to the Board’s legal determina-
tion of obviousness; the Board’s underlying factual findings
are reviewed for support by substantial evidence. In re
Gartside, 

, 1316 (Fed. Cir. 2000) (applying
the standards of the Administrative Procedure Act to PTO
findings and conclusions). Substantial evidence is “such
relevant evidence as a reasonable mind might accept as ad-
equate to support a conclusion.” Consol. Edison Co. v.
NLRB, 

, 229 (1938).
    The Board held that the Jentschel article, taken to-
gether with Japanese patent application JP947 in
IPR2015-01594, or together with JP947 and Japanese pa-
tent application JP755 in IPR2015-01600, renders claim 18
invalid for obviousness.
                 The Jentschel Article
     The Jentschel article discusses the problem presented
by wireless systems operating at differing frequencies, and
communication networks operating on differing stand-
ards, such as are used by cellular and wireless phone sys-
tems. Jentschel states that “the user would have to carry
at least two different cell phones.” Board Op. at *13 (quot-
ing Jentschel (translation) at 1). Jentschel presents the
solution of using a system that has a transceiver “the oper-
ating mode of which can be switched to different stand-
ards.” 

at 3–4). Jentschel describes
a “multimode direct-mixing receiver,” and depicts a “block
wiring diagram of a direct-mixing receiver (Direct Conver-
sion Receiver or DCR, zero-IF receiver) used as [a] multi-
mode receiver.” 

at 7, 10–13).
12    TELEFONAKTIEBOLAGET LM ERICSSON v. TCL CORPORATION




    The expert witnesses for both TCL and Ericsson agreed
that Jentschel’s direct-mixing receiver is described as con-
verting a received “HF [high frequency] signal in one step
(directly) to the low-frequency complex baseband signal by
means of a quadrature mixer pair. . . . [T]he mixers are
controlled by a complex LO [local oscillator].” 

at 7). The experts agreed that after quadrature
mixing, the channel is selected by two low pass filters.
Jentschel states the advantages of using a direct conver-
sion receiver. Jentschel at 8–9.
    The Jentschel article was found by the Board to show
the claim 18 limitation of “frequency dividing the oscillator
signal.” In IPR2015-01594, the Board cited the phase
shifter shown in Jentschel’s figure 2, along with Jentschel’s
identification of a frequency divider as a possible phase
shifter. In IPR2015-01600, the Board cited the phase
shifter in JP947, and found it would have been obvious to
“implement JP947’s phase shifter as a frequency divider”
based on Jentschel’s teachings. Board Op. at *31–32. The
Board found that Jentschel discloses all of the elements of
claim 18. As summarized by TCL:
          Jentschel explains the need for multimode cell
     phones, with “one transceiver . . . , the operating
     mode of which can be switched to different stand-
     ards.” Direct conversion receivers minimize dupli-
     cation of components: In a direct conversion
     multimode receiver, “[e]xcept for the antenna and
     the system filter, . . . the entire receiver part is com-
     pletely integrable.” Because of these advantages,
     “[t]he concept of the direct-mixing receiver is thus
     predestined for use in multimode cell phones.”
         It is undisputed that Jentschel explains that
     frequency dividers can be used as phase shifters,
     along with some advantages and disadvantages of
     doing so: “[B]roadband phase shifters can be as-
     sembled by means of frequency dividers . . . . The
TELEFONAKTIEBOLAGET LM ERICSSON v. TCL CORPORATION        13



    high phase accuracy and the constant amplitude
    ratio are advantageous . . . . However, the high
    power demand is disadvantageous.”
        It is also undisputed that Jentschel discloses
    resistive-capacitive (RC) phase shifters as another
    option that is “suitable” in at least some circum-
    stances.
TCL Br. 13 (citations omitted).
    Ericsson argues that Jentschel is a mere feasibility
study and not enabled. Ericsson points out that although
Jentschel mentions frequency dividers it does not require
the use of frequency dividers as a phase shifter, but dis-
closes RC [resistive-capacitive] phase shifters and conduct-
ing elements, as well as frequency dividers, for use as
possible phase shifters.
    The Board considered the arguments, and found that
Jentschel “express[ly] indicat[es] that phase shifters can be
implemented using frequency dividers,” Board Op. at *24,
and that “although Jentschel identifies advantages and
disadvantages of using a frequency divider, Jentschel does
not criticize, discredit or discourage the use of a frequency
divider.” 

The Board referred to Jentschel Fig-
ure 2, which shows a phase shifter, and the passage dis-
cussing phase shifters that states frequency dividers are a
possible phase shifter. The Board found that even if
Jentschel’s Figure 2 is viewed as showing an RC phase
shifter, not a frequency divider, these alternatives are de-
scribed by Jentschel as known alternatives serving the
same function.
    In response to Ericsson’s argument that Jentschel does
not provide the requisite motivation to select a frequency
divider to shift phases, the Board observed that Jentschel
expressly describes three possible phase shifters: (1) con-
ducting elements (2) frequency dividers and (3) RC phase
shifters. 

The Board found that Jentschel
14    TELEFONAKTIEBOLAGET LM ERICSSON v. TCL CORPORATION




teaches “broadband phase shifters can be assembled by
means of frequency dividers, whereby one divider each for
the I and Q channel is controlled with twice the LO fre-
quency and clocked by opposite edges.” 

(quoting
Jentschel at 10). The Board found that the phase shifter
and the frequency divider are taught in Jentschel for the
same purpose as in the ’052 patent.
    The Board also found that a skilled artisan would have
reason to “implement JP947’s phase shifter as a frequency
divider, in order to generate accurate, frequency independ-
ent I and Q [local oscillator] signals with a small, integra-
ble footprint, while minimizing statistical variations.” 

    Ericsson states that Jentschel “teaches away” from the
potential use of a frequency divider because Jentschel
states “the high power demand is disadvantageous.”
Jentschel at 10. Ericsson states that “if a frequency divider
is used, the local oscillator (LO) generates a signal at a fre-
quency that is twice the center of the radio signal to be re-
ceived,” and that the use of a frequency divider is
incompatible with the teachings of Jentschel. Ericsson Br.
44 (emphasis in original). TCL responds that Figure 2 of
Jentschel provides the motivation to use, or at least ren-
ders it obvious to try, a frequency divider, for Figure 2 of
Jentschel does not specify the type of phase shifter in its
block diagram of a “direct-mixing receiver (Direct Conver-
sion Receiver or DCR, zero-IF receiver) used as [a] multi-
mode receiver.” (Jentschel at 7).
     The Jentschel teaching is as follows:
     The phase shifter provides the mixer of the Q chan-
     nel with an LO signal which is phase-shifted rela-
     tive to the I signal. Phase shifters on the basis of
     conducting components have dimensions in the fre-
     quency range below 2 GHz which prevent integra-
     tion. However, broadband phase shifters can be
     assembled by means of frequency dividers,
TELEFONAKTIEBOLAGET LM ERICSSON v. TCL CORPORATION         15



    whereby one divider each for the I and Q channel
    is controlled with twice the LO frequency and
    clocked by opposite edges. The outputs subse-
    quently generate two signals phase-shifted by 90°.
    The high phase accuracy and the constant ampli-
    tude ratio are advantageous, so no adjustment to
    the respective receive frequency is required during
    multimode operation. However, the high power de-
    mand is disadvantageous.
Jentschel at 10. The Board found that this passage teaches
the use of frequency dividers to assemble phase shifters.
Board Op. at *24.
    Ericsson argues that Jentschel does not teach that fre-
quency dividing should be used, because Jentschel dis-
cusses the disadvantages as well as advantages of using a
frequency divider. Ericsson states that “Jentschel as a
whole discloses . . . that RC phase shifters are preferred
over frequency dividers.” Ericsson Br. 46. Ericsson argues
that Jentschel is fairly read as teaching away from use of
frequency dividers as a preferred solution.
    The Board found that Jentschel’s statement concerning
high power demand as a disadvantage of frequency divid-
ers was not a “teaching away,” for Jentschel states that
“phase shifters can be assembled by means of frequency di-
viders.” Board Op. at *24 (quoting Jentschel at 10).
Jentschel’s Figure 2 does not indicate a specific form of
phase shifter. The Board found that “We do not agree that
Jentschel’s discussion of advantages and disadvantages of
using a frequency divider or indicating that another com-
ponent is suitable rises to the level of a teaching away.” 

    The Board correctly summarized the general rule that
a reference teaches away “when a person of ordinary skill,
upon reading the reference, would be discouraged from fol-
lowing the path set out in the reference, or would be led in
a direction divergent from the path that was taken by the
16   TELEFONAKTIEBOLAGET LM ERICSSON v. TCL CORPORATION




applicant.” 

re Mouttet, 

,
1333–34 (Fed. Cir. 2012)). The Board found that although
Jentschel recites the disadvantage of the high power de-
mand of frequency dividers, Jentschel does not suggest
that this mode of phase shifting would be ineffective in
achieving the high phase accuracy required of frequency
dividers. Jentschel does not criticize, discredit, or discour-
age the technological efficacy of a frequency divider for
phase shifting. 

that substantial evidence supports the
Board’s finding that Jentschel renders obvious the claim 18
“steps of generating a first oscillator signal and frequency-
dividing the first oscillator signal to generate the in-phase
and quadrature oscillator signals prior to the step of mix-
ing.” 

(quoting claim 18).
                The Japanese References
    Japanese Application Publication No. H05-121947
(“JP947”), published May 18, 1993, describes “a direct con-
version reception system . . . that amplif[ies], separately in
multiple frequency bands, the weak high-frequency signal
from a multiband antenna.” JP947 Abstract (Translation).
Japanese Application Publication No. H5-160755
(“JP755”), published June 25, 1993 is similar in disclosure.
The Board held in IPR2015-01584 that the Jentschel refer-
ence in view of JP947 renders obvious the subject matter of
claim 18. The Board held in IPR2015-01600 that the Jap-
anese references fill any perceived gap in rendering it ob-
vious to use a frequency divider as the phase shifter.
     The JP947 direct conversion system is described as ap-
plicable to FM broadcasting, AM broadcasting, and satel-
lite broadcasting, and provides direct conversion among
these systems. JP947 ¶ 16. The JP947 system includes a
multiband antenna, an AM high-frequency amplifier, AM
and FM high-frequency filters, a mixer that transforms the
output signals of the FM filter and AM filters into an
TELEFONAKTIEBOLAGET LM ERICSSON v. TCL CORPORATION        17



orthogonal signal, and an oscillator for mixing the received
signals and forming an orthogonal signal. 

     The Board held that the Jentschel article together with
the JP947 system’s phase shifter renders claim 18 obvious.
Ericsson argues that the Japanese and the Jentschel refer-
ences deal with different systems, and that the Board erred
by selecting portions of Jentschel and combining a portion
of the JP947 system. Ericsson Br. 46. Ericsson argues that
there is no teaching or motivation in the references to com-
bine these different embodiments. Ericsson also states
that the Japanese references do not teach that a frequency
divider could be used successfully.
    The Board found that a skilled artisan would have been
motivated to “implement JP947’s phase shifter as a fre-
quency divider, in order to generate accurate, frequency in-
dependent I and Q [local oscillator] signals with a small,
integrable footprint, while minimizing statistical varia-
tions.” Board Op. at *32. The Board stated that Jentschel’s
teachings would have motivated an artisan to do so because
of “Jentschel’s teachings of the advantages and the disad-
vantages associated with RC shifters, . . . [and] Jentschel’s
teaching that problems with generating in-phase and
quadrature local oscillator signals using RC phase shifters
can be overcome using a frequency divider.” 

    We conclude that substantial evidence supports the
Board’s findings and conclusions, whereby the subject mat-
ter of claim 18 would have been obvious. The Board’s deci-
sions in IPR2015-01584 and IPR2015-01600 are affirmed.
                       AFFIRMED
    Each party shall bear its costs.