NOTE: This disposition is nonprecedential.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 Mariana 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 defendants-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 Incorporated; and DARIN W. SNYDER and MELODY DRUMMONDHANSEN, 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, Massachusetts. 

______________________ 

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 following 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. CV12-5908-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) upconverting 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 receiving 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”) receivers; 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 influenced 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 undistorted half). The Hotto patents refer to the method of replacing 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 representative. 

 
AMERICAN RADIO LLC v. QUALCOMM INC. 5

from the antenna and generating a reconstructed waveform having substantially no 

distortions therein, wherein the reconstruction circuit includes: 

an analog to digital converter (ADC) electrically connected to the antenna for receiving the analog rf signal therefrom and 

outputting a digitized rf signal in response; 

a digital processor electrically connected to 

the ADC for receiving the digitized rf 

signal and in response outputting the reconstructed waveform in accordance with 

a predetermined reconstruction paradigm.

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 digitized signal representing the rf signal; and

a digital processor electrically connected to the 

ADC, the digital processor being programmed with software to decode and extract 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 “Qualcomm”) 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 construed 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 “electromagnetic signal” (collectively “analog signal limitations”) 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” limitation to mean “replacing a distorted portion of the input 

waveform at the carrier frequency with an undistorted 

portion, wherein the operand of the reconstruction operation 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 jurisdiction 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.” American Radio contends that the limitations should be construed 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 describe 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 regarding 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, sinusoidallyshaped 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 important to recognize that these references in the specification to “rf signal” and analog signals received by the 

antenna necessarily mean a signal at the carrier frequency. Id. col. 1 ll. 19–20 (noting that the modulated information “is carried by the received rf signal”); id. col. 1 ll. 

21–23 (noting that “rf signals are corrupted by environmental 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 construction. 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 “digitized 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 digitized rf signal”); id. col. 4 ll. 47–48 (referring to a component 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 digitized 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 superheterodyne receivers. Additionally, it argues that allowing a direct downconversion ignores the “intermediate” 

aspect of intermediate frequency.

Qualcomm responds that the district court’s construction 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 construction broadens the scope of the claims by allowing 

them to cover a signal that has been directly downconverted 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 . . . whether 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 conversion 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 downconverting the signal. Id. col. 1 ll. 55–63 (“[I]t would be advantageous to accomplish [reconstruction] prior to the nonlinear 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 irrecoverable and therefore precludes identification of some distortion 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 construction 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 reconstruction 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 replacing distorted portions of the waveform with undistorted 

ones. See, e.g., id. col. 1 ll. 51–55 (“[I]t would be advantageous 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 undistorted half, after which “the distorted portion is replaced with the inverse of the corresponding waveform 

portion” one wave at a time); id. col. 7 ll. 48–60 (describing 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 (describing replacing distorted portions of the input waveform 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. According to American Radio, that construction renders superfluous 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 undistorted 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 “replacing a distorted portion of the input waveform with an 

undistorted portion.” 

The parties in this case stipulated that, under the district 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