       NOTE: This disposition is nonprecedential.


  United States Court of Appeals
      for the Federal Circuit
                ______________________

              AMERICAN RADIO LLC,
                Plaintiff-Appellant,

                           v.

           QUALCOMM INCORPORATED,
                Defendant-Appellee,

                          AND

               CISCO SYSTEMS, INC.,
                 Defendant-Appellee,

                          AND

               INTEL CORPORATION,
                  Defendant-Appellee,

                          AND

            BROADCOM CORPORATION,
                 Defendant-Appellee.
               ______________________

             2013-1641, -1642, -1643, -1644
                ______________________

   Appeals from the United States District Court for the
Central District of California in Nos. 12-CV-1123, 12-CV-
2                     AMERICAN RADIO LLC   v. QUALCOMM INC.



5908, 12-CV-5909, and 12-CV-5910, Senior Judge Maria-
na R. Pfaelzer.
                ______________________

                Decided: August 22, 2014
                 ______________________

    THOMAS G. PASTERNAK, Steptoe & Johnson LLP, of
Chicago, Illinois, argued for plaintiff-appellant. With him
on the brief were MEREDITH MARTIN ADDY and THOMAS A.
RAMMER, II.

    DAVID C. MARCUS, Wilmer Cutler Pickering Hale and
Dorr LLP, of Los Angeles, California, argued for all de-
fendants-appellees. With him on the brief were ANDREA
WEISS JEFFRIES, of Los Angeles, California, GREGORY P.
TERAN, LAUREN B. FLETCHER, KEVIN A. GOLDMAN, and
PROSHANTO MUKHERJI, of Boston, Massachusetts, for Intel
Corporation. On the brief were L. NORWOOD JAMESON,
MATTHEW S. YUNGWIRTH and JOHN R. GIBSON, Duane
Morris, LLP, of Atlanta, Georgia, for Cisco Systems, Inc.;
DAVID A. NELSON and MARC L. KAPLAN, Quinn Emanuel
Urquhart & Sullivan LLP, of Chicago, Illinois, JUSTIN C.
GRIFFIN, of Los Angeles, California, and JENNIFER A.
KASH, of San Francisco, California, for Qualcomm Incor-
porated; and DARIN W. SNYDER and MELODY DRUMMOND-
HANSEN, O’Melveny & Myers LLP, of San Francisco,
California, for Broadcom Corporation. Of counsel for Intel
Corporation was JORDAN LAWRENCE HIRSCH, Wilmer
Cutler Pickering Hale and Dorr, of Boston, Massachu-
setts.
                  ______________________

    Before LOURIE, O’MALLEY, and CHEN, Circuit Judges.
LOURIE, Circuit Judge.
    American Radio LLC (“American Radio”) appeals from
the judgment of noninfringement of the United States
AMERICAN RADIO LLC   v. QUALCOMM INC.                      3



District Court for the Central District of California follow-
ing stipulation by the parties after the court construed
several claim limitations of U.S. Patents 5,864,754 (the
“’754 patent”), 7,831,233 (the “’233 patent”), 8,045,942
(the “’942 patent”), 8,170,519 (the “’519 patent”), and
8,280,334 (the “’334 patent”) (collectively, “the Hotto
patents”). See Am. Radio, LLC v. Qualcomm Inc., No. CV-
12-5908-MRP (C.D. Cal. Aug. 29, 2013), ECF No. 78
(“Stipulation of Noninfringement”); Am. Radio, LLC v.
Qualcomm Inc., No. CV-12-5908-MRP, 2013 WL 3270404
(C.D. Cal. May 23, 2013) (“Claim Construction Order”).
Because the district court did not err in construing the
claims of the Hotto patents, and its consequent judgment
of noninfringement, we affirm.
                       BACKGROUND
    In radio technology, digital information is transmitted
by: (1) converting that information into a low frequency
analog signal known as the baseband signal; (2) upcon-
verting the baseband signal into a high frequency signal
known as the carrier signal by changing, or “modulating,”
the baseband signal with a higher frequency one; (3)
transmitting the modulated carrier signal; (4) receiving
the transmitted modulated carrier signal; and (5)
downconverting the received carrier signal in one or more
steps to the baseband signal to extract the information.
See Claim Construction Order, 2013 WL 3270404, at *2.
    For the downconversion of the carrier signal, the re-
ceiving system can either directly downconvert it to the
baseband frequency, or it can downconvert it to another
frequency using a process involving two or more steps
before extracting the baseband signal. Receivers that
directly downconvert the carrier signal are referred to as
“homodyne” or “zero-IF” (“intermediate frequency”) re-
ceivers; those that downconvert a signal using two or
more steps are referred to as “superheterodyne” receivers.
See id. at *11.
4                       AMERICAN RADIO LLC   v. QUALCOMM INC.



     Received radio frequency (“rf”) signals can be influ-
enced by outside signals and environmental factors, which
introduce distortion to the transmitted signal. ’754 patent
col. 1 ll. 20–22. After the radio signal has been received,
the receiver can use a variety of techniques to remove the
distortion, or noise, from that signal. See, e.g., id. col. 7 l.
13–col. 8 l. 11.
    American Radio owns the Hotto patents, which share
a common specification; all derive from the same initial
application. * The patents disclose systems and methods
for correcting noisy signals by replacing the distorted
sections of the signal with undistorted portions. E.g., id.
col. 5 ll. 59–65 (describing a method of identifying the
distorted portions of a received waveform and replacing
those portions with undistorted portions); id. col. 1 ll. 51–
58 (describing a method of analyzing both “halves” of the
signal and replacing the distorted half with the undistort-
ed half). The Hotto patents refer to the method of replac-
ing distorted portions of a signal with undistorted
portions as “reconstruction.”
    Claim 10 of the ’754 patent is representative of the
claims at issue and recites a receiver that receives an
analog signal, digitizes that signal, and “reconstructs” the
signal to remove distortion. That claim reads as follows:
    10. An rf receiver, comprising:
        an antenna;
        a reconstruction circuit electrically connected to
           the antenna for receiving an analog rf signal



    *   The district court and the parties each treat the
specification of the ’754 patent as representative of all of
the Hotto patents. See Appellant’s Br. 3 n.1. Accordingly,
we also treat the ’754 patent specification as representa-
tive.
AMERICAN RADIO LLC     v. QUALCOMM INC.                    5



           from the antenna and generating a recon-
           structed waveform having substantially no
           distortions therein, wherein the reconstruc-
           tion circuit includes:
           an analog to digital converter (ADC) electri-
              cally connected to the antenna for receiv-
              ing the analog rf signal therefrom and
              outputting a digitized rf signal in re-
              sponse;
           a digital processor electrically connected to
              the ADC for receiving the digitized rf
              signal and in response outputting the re-
              constructed waveform in accordance with
              a predetermined reconstruction para-
              digm.
Id. col. 9 l. 63–col. 10 l. 11.
    Claim 1 of the ’942 patent is representative of
other claims at issue and recites a receiver that is
similar to the one that is recited in claim 10 of the
’754 patent, but also requires that the received signal
not be downconverted to IF before it is digitized; it
reads as follows:
    1. A receiver, comprising:
       an analog to digital converter (ADC) receiving
          as input an rf signal that has not been
          downconverted in the analog domain to IF
          by the receiver, the ADC outputting a digit-
          ized signal representing the rf signal; and
       a digital processor electrically connected to the
          ADC, the digital processor being pro-
          grammed with software to decode and ex-
          tract baseband information from the
          digitized signal.
6                      AMERICAN RADIO LLC   v. QUALCOMM INC.



’942 patent col. 8 ll. 38–46. All of the contested claim
limitations are in the above-recited claims.
    American Radio sued Qualcomm Inc., Cisco Systems
Inc., Intel Corp., and Broadcom Corp. (collectively “Qual-
comm”) asserting that Qualcomm infringed claim 1 of the
’754 patent; claims 1, 2, and 3 of the ’519 patent; claim 10
of the ’233 patent; claims 1, 2, and 3 of the ’942 patent;
and claim 29 of the ’334 patent. The district court con-
strued the claim terms “analog signal,” “digitized signal,”
“IF,” and “reconstruction.” Claim Construction Order,
2013 WL 3270404, at *3–16.
     First, the district court construed the terms “analog rf
signal,” “rf signal,” “analog sinusoidal signal,” and “elec-
tromagnetic signal” (collectively “analog signal limita-
tions”) to mean the “waveform at the carrier frequency,”
relying on the Hotto patents’ use of the analog signal
limitations to describe the carrier signal received by the
antenna. Id. at *11. Secondly, the court construed the
“digitized signal” limitation to mean the digitized version
of the analog signal. Id. Third, the court construed “IF”
to mean any “frequency to which the input signal is
shifted, including shifting the signal to zero Hertz,” which
it gleaned from usage of IF in the prior art. Id. at *12–13.
Finally, the court construed the “reconstruction” limita-
tion to mean “replacing a distorted portion of the input
waveform at the carrier frequency with an undistorted
portion, wherein the operand of the reconstruction opera-
tion represents one full wave or cycle,” in view of the
consistent use of the term in the specification. Id. at *16.
After the court issued its claim construction opinion, the
parties stipulated to a judgment of noninfringement of all
asserted claims. Stipulation of Noninfringement at 2–3.
    American Radio timely appealed. We have jurisdic-
tion pursuant to 28 U.S.C. § 1295(a)(1).
AMERICAN RADIO LLC   v. QUALCOMM INC.                        7



                         DISCUSSION
    The words of a claim in a patent are generally given
their ordinary and customary meaning, which is the
meaning that a term would have to a person of ordinary
skill in the art after reviewing the intrinsic record at the
time of the invention, i.e., as of the effective filing date of
the patent application. Phillips v. AWH Corp., 415 F.3d
1303, 1312–13 (Fed. Cir. 2005). The intrinsic record
includes the claims, the specification, and the prosecution
history. E.g., Vitronics Corp. v. Conceptronic, Inc., 90
F.3d 1576, 1582 (Fed. Cir. 1996). The claims “‘must be
read in view of the specification, of which they are a
part.’” Phillips, 415 F.3d at 1315 (quoting Markman v.
Westview Instruments, Inc., 52 F.3d 967, 979 (Fed. Cir.
1995) (en banc), aff’d, 517 U.S. 370 (1996)).
                              A.
    We first consider the construction of the analog signal
limitations and the digitized signal limitation. American
Radio argues that the district court erred in construing
both the analog signal and digitized signal claim terms as
limited to “the waveform at the carrier frequency.” Amer-
ican Radio contends that the limitations should be con-
strued in accordance with the plain meaning of the term
“signal,” which is “a waveform that carries information.”
Appellant’s Br. 44–45.
    Qualcomm responds that each asserted claim uses the
analog signal limitations to describe a signal that is
received and then digitized. Qualcomm further argues
that although the term signal may simply relate to a
waveform, the Hotto patents use “analog signal” to de-
scribe a specific type of waveform, namely the waveform
at the carrier frequency, and use “digitized signal” to
describe the digitized version of that analog signal.
   We agree with Qualcomm and the district court re-
garding the proper construction of the analog signal
8                      AMERICAN RADIO LLC   v. QUALCOMM INC.



limitations and the claim term “digitized signal,” because
the Hotto patents consistently use the signal limitations
to describe a waveform at the carrier frequency. As an
initial matter, although American Radio argues that the
district court misconstrued the plain meaning of the term
“signal,” the court separately construed the analog signal
limitations, Claim Construction Order, 2013 WL 3270404,
at *3, and then addressed the digitized signal limitation,
id. at *10–11. Accordingly, we address those limitations
separately.
    Regarding the analog signal limitations, the written
description of the ’754 patent consistently uses the analog
signal limitations to refer to the analog signal at the
carrier frequency. See, e.g., ’754 patent col. 1 ll. 20–22
(referring to the fact that “rf signals are corrupted by
environmental factors during transmission”); id. col. 4 ll.
6–11 (referring to the rf signal as “an analog, sinusoidally-
shaped signal that is relatively smooth and undistorted
when transmitted”); id. col. 4 ll. 40–45 (describing an
analog-to-digital converter as connected to the antenna
“for receiving the analog signal therefrom”). It is im-
portant to recognize that these references in the specifica-
tion to “rf signal” and analog signals received by the
antenna necessarily mean a signal at the carrier frequen-
cy. Id. col. 1 ll. 19–20 (noting that the modulated infor-
mation “is carried by the received rf signal”); id. col. 1 ll.
21–23 (noting that “rf signals are corrupted by environ-
mental factors during transmission”).
    Additionally, the figures of the ’754 patent describe
the “rf signal” as propagating until it is received by the
antenna, further supporting the district court’s construc-
tion. Id. col. 4 ll. 3–19. The asserted claims, likewise,
consistently use the analog signal limitations in the same
manner. See, e.g., id. col. 9 l. 9–col. 10 l. 10 (requiring an
antenna “for receiving an analog rf signal”).
AMERICAN RADIO LLC   v. QUALCOMM INC.                         9



     Moreover, the ’754 patent consistently refers to a “dig-
itized signal” as the digitized version of the analog signal.
See, e.g., id. col. 4 ll. 42–45 (describing an ADC converter
that receives the “analog rf signal” and “outputs a digit-
ized rf signal”); id. col. 4 ll. 47–48 (referring to a compo-
nent that “receives the digitized signal from the ADC”).
Additionally, the asserted claims support the district
court’s construction of digitized signal. See, e.g., id. col. 10
ll. 3–6 (requiring an ADC for “receiving the analog signal .
. . and outputting a digitized rf signal in response”).
    The patent thus consistently uses the analog signal
limitations to refer to the analog signal at the carrier
frequency and uses digitized signal to refer to the digit-
ized version of that analog signal. The district court thus
did not err in construing those limitations accordingly.
See Honeywell Intern., Inc. v. ITT Indus., Inc., 452 F.3d
1312, 1318 (Fed. Cir. 2006) (affirming the district court’s
construction of a claim term because of the consistent use
of that term in the written description).
                              B.
    We next consider the construction of the IF limitation.
American Radio argues that the IF limitation should be
construed as any intermediate frequency between the
carrier frequency and the baseband frequency, but not
including the baseband frequency.        American Radio
contends that the specification consistently distinguishes
the invention of the Hotto patents from prior art super-
heterodyne receivers. Additionally, it argues that allow-
ing a direct downconversion ignores the “intermediate”
aspect of intermediate frequency.
    Qualcomm responds that the district court’s construc-
tion is consistent with the plain and ordinary meaning of
IF and that the intrinsic record highlights that shifting
the frequency directly to the baseband frequency of zero
Hertz nonetheless produces an “IF” frequency. Qualcomm
argues that adopting American Radio’s construction
10                     AMERICAN RADIO LLC   v. QUALCOMM INC.



would necessarily broaden the claim scope to encompass a
directly downconverted signal. Specifically, Qualcomm
contends that because claim 1 of the ’942 patent recites IF
as a negative limitation, i.e., requiring that the signal not
have been downconverted to IF, American Radio’s con-
struction broadens the scope of the claims by allowing
them to cover a signal that has been directly downcon-
verted to the baseband frequency, but not one that has
been downconverted to some frequency between the
carrier frequency and the baseband frequency.
    We agree with Qualcomm and the district court that
the meaning of the claim term IF, as understood by those
skilled in the art, includes shifting the signal to the
baseband frequency or zero Hertz. “[P]rior art . . . wheth-
er or not cited in the specification or the file history . . .
can often help to demonstrate how a disputed term is
used by those skilled in the art.” Vitronics, 90 F.3d at
1584. U.S. Patent 4,733,403, cited in the ’942 patent
states that “[g]enerally, any receiver with an intermediate
frequency of zero Hertz is referred to as a direct conver-
sion receiver.” U.S. Patent 4,733,403 col. 1 ll. 20–22. The
district court also relied on U.S. Patent 4,709,402, which
states that “[t]he description is also applicable where the
receiver is of the homodyne type, i.e., its intermediate
frequency is zero [Hertz].” U.S. Patent 4,709,402 col. 5 ll.
64–65. Although that patent was not cited in the ’942
patent, it is nonetheless relevant to determining how IF
would be read by those skilled in the art. Vitronics, 90
F.3d at 1584. Based on these disclosures, the district
court concluded that one skilled in the art at the time
would understand that IF can include a frequency of zero
Hertz.
    Additionally, the portions of the specification that
American Radio relies on to differentiate the invention of
the Hotto patents from conventional uses of IF do not
alter that definition. The written description of the ’754
patent includes the statement that conventional super-
AMERICAN RADIO LLC   v. QUALCOMM INC.                      11



heterodyne structures downconvert “the received signal
down to an intermediate frequency (IF) [that] is then sent
through a bandpass filter and demodulated . . . to recover
the information (colloquially referred to as ‘baseband’)
that is carried by the received rf signal.” ’754 patent col. 1
ll. 13–19.     However, that statement highlights that
downconverting to an intermediate frequency before error
correction can cause some of the signal information to be
permanently lost, and teaches that the invention of the
’754 patent performs error correction before downconvert-
ing the signal. Id. col. 1 ll. 55–63 (“[I]t would be advanta-
geous to accomplish [reconstruction] prior to the non-
linear transformation of the rf signal to the IF signal
during mixing by the oscillator . . . since the mixing
function causes certain data in the signal to be irrecover-
able and therefore precludes identification of some distor-
tion and corruption in the ‘true’ signal post-mixing.”).
Accordingly, the district court did not err in relying on the
prior art to construe IF to mean any “frequency to which
the input signal is shifted, including shifting the signal to
zero Hertz.”
                             C.
    We finally consider the district court’s construction of
the claim term “reconstruction.” American Radio argues
that the reconstruction limitation should be construed as
“reducing errors in communication signals” in accordance
with the plain meaning of the term. Appellant’s Br. 55–
56. American Radio contends that the district court
imported limitations from the specification into its con-
struction to require replacing a part of the waveform. It
also argues that the district court’s construction renders
several dependent claims of the patent superfluous.
    Qualcomm responds that the term “reconstruction”
has no plain meaning in the art and that the specification
consistently uses reconstruction to refer to instances
where parts of the received signal are replaced with
12                     AMERICAN RADIO LLC   v. QUALCOMM INC.



undistorted portions of the received signal. Qualcomm
contends that although the other limitations the district
court read into the term “reconstruction”—“at the carrier
frequency” and “wherein the operand of the reconstruc-
tion cycle represents one full wave or cycle”—are properly
part of the term as used in claim 10 of the ’754 patent, it
need not rely on those limitations because the accused
devices simply do not replace distorted portions of the
input waveform with undistorted ones. American Radio
does not disagree that the district court’s conclusion that
distorted portions of the input waveform must be replaced
with undistorted ones is determinative of its infringement
claims, without reference to the additional limitations.
    We again agree with Qualcomm and the district court
that the claim term “reconstruction” refers to replacing a
distorted portion of the signal with undistorted ones. The
specification consistently uses reconstruction to mean
replacing the distorted portion of the input waveform.
The written description of the ’754 patent repeatedly
describes reconstruction as being accomplished by replac-
ing distorted portions of the waveform with undistorted
ones. See, e.g., id. col. 1 ll. 51–55 (“[I]t would be advanta-
geous to analyze both the positive and negative halves of
an rf signal cycle and determine which half is the ‘best’
half, and then extract the useful signal from the ‘best’
half.”); id. col. 7 ll. 24–46 (describing comparing the
halves of the waveform to determine which is the un-
distorted half, after which “the distorted portion is re-
placed with the inverse of the corresponding waveform
portion” one wave at a time); id. col. 7 ll. 48–60 (describ-
ing a fast Fourier transform reconstruction wherein
distorted portions of the waveform are replaced by smooth
portions of the waveform); id. col. 7 l. 61–col. 8 l. 11 (de-
scribing replacing distorted portions of the input wave-
form with smooth portions based on a “wavelet analysis”).
    Additionally, the district court’s construction of the
claim term “reconstruction” does not render any depend-
AMERICAN RADIO LLC   v. QUALCOMM INC.                     13



ent claims of the asserted patents superfluous. American
Radio points to claims 3 and 4 of the ’942 patent to argue
that under the district court’s construction, claim 3’s
reconstruction limitation requires replacing distorted
portions of the signal with undistorted portions. Accord-
ing to American Radio, that construction renders super-
fluous the language of claim 4, which depends from claim
3, requiring “replacing at least one distorted portion of the
signal with a replacement portion that is based on at least
some undistorted portions of the signal.” ’942 patent col.
8 ll. 64–67. However, the district court’s construction of
the claim term “reconstruction” only requires that a
distorted portion of the signal be replaced with an un-
distorted portion and does not limit the source of that
undistorted portion. Claim 4, on the other hand, requires
that the replacement portion of the signal be based on at
least some undistorted portions of the received signal, and
is therefore narrower than the district court’s construction
of the reconstruction limitation. The district court thus
did not err in construing reconstruction to mean “replac-
ing a distorted portion of the input waveform with an
undistorted portion.”
     The parties in this case stipulated that, under the dis-
trict court’s claim constructions, Qualcomm does not
infringe the asserted claims. Because we have affirmed
the court’s relevant claim constructions, we accordingly
affirm the judgment of noninfringement.
                        CONCLUSION
    For the foregoing reasons, the decision of the district
court construing the analog signal, digitized signal, IF,
and reconstruction limitations of the Hotto patents, and
hence the judgment of noninfringement, are affirmed.
                       AFFIRMED
