No. 08-964 
In The 
Supreme Court of the United States 
----------------- ♦ ----------------- 
JOHN J. DOLL, Acting Under Secretary of Commerce 
for Intellectual Property and Acting Director of the 
United States Patent and Trademark Office, 
----------------- ♦ ----------------- 
On Writ Of Certiorari To The 
United States Court Of Appeals 
For The Federal Circuit 
----------------- ♦ ----------------- 
----------------- ♦ ----------------- 
235 Montgomery Street 
San Francisco, CA 94105 
(415) 954-4400 
Counsel for Amici Curiae 
*Counsel of Record 
OR CALL COLLECT (402) 342-2831 

    Whether the Federal Circuit erred by holding 
that a “process” must be tied to a particular machine 
or apparatus, or transform a particular article into a 
different state or thing (“machine-or-transformation” 
test), to be eligible for patenting under 35 U.S.C. 
§ 101, despite this Court’s precedent declining to limit 
the broad statutory grant of patent-eligibility for 
“any” new and useful process beyond excluding 
patents for “laws of nature, physical phenomena, and 
abstract ideas.” 
  Whether the Federal Circuit’s “machine-or-
transformation” test for patent-eligibility, which 
effectively forecloses meaningful patent protection to 
many business methods, contradicts the clear 
Congressional intent that patents protect “method[s] 
of doing or conducting business.” 35 U.S.C. § 273(a)(3).* 
    *  The  Amici’s argument is limited to the first question 
presented: whether the machine-or-transformation test is an 
appropriate test for patentability. The Amici do not express an 
opinion on the second question on which certiorari was granted. 

QUESTIONS PRESENTED ..................................  

STATEMENT OF INTEREST................................  

MENT ..................................................................   

ARGUMENT ...........................................................  


A.   The “Machine-or-Transformation Test” 
Is Ambiguous As Applied To “Informa-
tion Age” Inventions Like Digital Sig-
nal Processing, Because Such Inventions 
Operate On Data And Waveforms 
Rather Than Physical “Articles” ...........  

B.    Bilski Admits Its Own Troubling Am-
biguity ....................................................   

C.    Application  Of  Bilski Has Caused 
Serious Problems ...................................    10 
The Machine-or-Transformation Test 
Elevates Form Over Substance ............   11 

A.    Under  Diehr’s Holding, The Only 
Exclusions From Patent-Eligibility Are 
“Laws Of Nature, Natural Phenomena, 
And Abstract Ideas” ...............................   12 
B.    Diehr’s Practical Application Require-
ment Did Not Require Transformation 
Of Physical “Articles” ............................   15 
FORMATION AGE ......................................   18 
A.    Decades  Of  Post-Diehr Federal Circuit 
Precedent Confirm That Data And 
Waveform Transformation, Including 
Practical Applications of Digital Signal 
Processing, Are Properly Patent-
Eligible ...................................................    18 
B.    If  Bilski’s Invention Is To Be Rejected 
Based On The Non-Technical Nature 
Of The Invention, The Standard Ap-
plied Should Be Precise And Unambig-
uous ........................................................    22 
CONCLUSION .......................................................   22 

In re Abele, 684 F.2d 902 (Cust. & Pat. App. 
1982) ............................................................ 17, 18, 19 
In re Alappat, 33 F.3d 1526 (Fed. Cir. 1994) ....... 15, 17 
Arrhythmia Research Tech., Inc. v. Corazonix 
Corp., 958 F.2d 1053 (Fed. Cir. 1992) ........... 3, 19, 20 
In re Bilski, 545 F.3d 943 (Fed. Cir. 2008) ......... passim 
Cochrane v. Deener, 94 U.S. 780 (1876) ..................... 12 
Diamond v. Chakrabarty, 447 U.S. 303 (1980) ......... 17 
Diamond v. Diehr, 450 U.S. 175 (1981) ............. passim 
Gottschalk v. Benson, 409 U.S. 63 
(1972) ............................................... 13,  14, 15, 16, 17 
Mackay Radio & Telegraph Co. v. Radio Corp. 
of America, 306 U.S. 86 (1939) ............................... 14 
In re Nuijten, 500 F.3d 1346 (Fed. Cir. 
2007) .......................................................... 6,  7, 20, 21 
Parker v. Flook, 437 U.S. 584 (1978) .... 13, 14, 15, 16, 17 
U.S. Const. Art. I, Section 8 ................................... 4, 22 
35 U.S.C. § 101 ................................................... passim 
35 U.S.C. § 273(a)(3) .....................................................  i 

Dolby Laboratories (“Dolby”), DTS, Inc. (“DTS”) 
and SRS Labs, Inc. (“SRS”) (herein “Amici”) develop 
and deliver audio products and technologies that 
make the entertainment experience more realistic 
and immersive. 
Dolby has over 1100 employees, including techni-
cians, engineers, researchers and scientists who are 
vital to Dolby’s patent process. Its worldwide portfolio 
includes over 1500 issued patents and over 2000 
pending applications. For more than four decades, 
Dolby has provided high-quality audio and surround 
sound in cinema, broadcast, home audio systems, 
cars, DVDs, headphones, games, televisions, and 
personal computers. Dolby’s technologies have been 
included in more than 3 billion products through 
licenses with major manufacturers throughout the 
world. For fiscal year 2007, Dolby spent more than 
$44 million for research and development and for 
fiscal year 2008 more than $62 million.1 
DTS is a major provider of high quality branded 
entertainment technologies, which have been incorpo-
rated in hundreds of millions of consumer electronics 
products manufactured and sold globally by licensee 
1  The parties have consented to the filing of this brief. No 
counsel for a party authored this brief in whole or in part, and 
no counsel or party made a monetary contribution intended to 
fund the preparation or submission of this brief. No person other 
than  Amici, their members, or their counsel made a monetary 
contribution to this brief ’s preparation or submission. 

customers. It has a substantial base of intellectual 
property assets, including 42 patent families and 110 
individual patents granted worldwide. 
SRS develops audio technologies that enable 
users to enjoy natural, restored sound from a wide 
variety of audio devices. Billions of people worldwide 
have purchased audio devices that use SRS’ 
technologies. These technologies include advanced 
audio enhancement, dialog clarity, voice intelligibility, 
and surround sound processing. SRS also has a large 
worldwide patent portfolio that includes over 100 
issued patents and dozens of pending applications.  
----------------- ♦ ----------------- 
In the 28 years since Diamond v. Diehr, 450 U.S. 
175 (1981), was decided, this Court has not addressed 
the growing ambiguity in Federal Circuit jurispru-
dence regarding the patentability of processes that 
apply scientific algorithms to bring into existence 
valuable new technological applications. Limiting 
patentable processes to those tied to particular 
machines or transformations of articles, as required 
by the standard set forth in In re Bilski, 545 F.3d 943 
(Fed. Cir. 2008), is not required by Title 35, Section 
101 of the United States Code as applied in Diehr, 
and will unreasonably foreclose valuable techno-
logical development.  

In the current information age, such a limitation 
risks discouraging innovation in new and unforeseen 
areas of technology. An example of such valuable 
technology that should be unquestionably patentable 
is the analysis of echocardiographic signals that 
measured heart rate as addressed in Arrhythmia 
Research Tech., Inc. v. Corazonix Corp., 958 F.2d 1053 
(Fed. Cir. 1992). Digital audio signals represent 
physical phenomena just the same as echocardio-
graphic signals do. Audio signal processing utilizes 
technology such as psychoacoustics to develop 
valuable processes for operating on, transforming and 
synthesizing new digital audio signals. This is 
precisely the kind of innovation that has resulted in 
the  Amici’s  numerous technological innovations that 
have enhanced the quality of entertainment.2 Prac-
tical applications of digital signal processing meet the 
criteria set forth in Diehr. The manipulation of an 
audio signal by application of scientific principles to 
achieve a result that has practical application is 
patentable irrespective of whether the process is tied 
to a particular machine or whether digital audio 
signals qualify as “articles.” 
2 Company founder Ray Dolby was awarded a Technical 
Grammy® from the Recording Academy for “ma[king] a contri-
bution of outstanding technical significance to the recording 
field.” Dolby has similarly received two Scientific and Engi-
neering Awards from the Academy of Motion Picture Arts and 
Sciences. DTS has also received a Scientific and Engineering 
Award from the Academy of Motion Picture Arts and Sciences. 

Bilski has introduced uncertainty into, and 
potentially narrowed the standard for, patentability 
that this Court should now clarify. Amici  take no 
position on whether the business method claims in 
Bilski should be rejected. But in the words of Judge 
Newman in dissent in Bilski, “[u]ncertainty is the 
enemy of innovation.” 545 F.3d at 977. If patentability 
of those claims is rejected, it should be because the 
concept of hedging risks in commodities trading is of 
a non-technical nature.3 That the Bilski  claims are 
not traditional industrial processes that transform 
physical articles is immaterial. The Court should not 
throw out the “babies” – patents for valuable 
technological innovations in the well-established field 
of signal processing – with what it may view as the 
“bathwater” of business method patents.  
----------------- ♦ ----------------- 
3  Article I, Section 8 of the U.S. Constitution sets forth the 
purpose of the U.S. Patent System as being “to promote the 
Progress of Science and useful Arts.” 

Although Bilski addressed only an application for 
a business method patent, the standard it adopted 
impacts a far wider range of inventions than just 
business methods. Under Bilski, a process is pat-
entable if it meets the exclusive test of being “(1) . . . 
tied to a particular machine or apparatus, or (2) 

] transform[ing] a particular article into a 
different state or thing.” Bilski, 545 F.3d at 954, 964-
65 (“the machine-or-transformation test is the only 
applicable test and must be applied”). This test is 
problematic because it calls into doubt whether 
information age inventions that operate on data or 
waveforms are eligible for patenting.  
Bilski test represents a significant departure 
from the standard for patent-eligibility set forth in 
Diehr.  Diehr established a narrow and well-defined 
set of exceptions to patentability, and required only 
that a process have practical application to be 
eligible. Under Diehr, information age technologies 
have routinely been held patent-eligible, and as a 
consequence, the field has flourished. Bilski threatens 
to disrupt the audio technology industry and under-
mine the settled expectations of intellectual property 

owners by substituting ambiguity in the place of 
Diehr’s certainty.  
A. The “Machine-or-Transformation Test” 
Is Ambiguous As Applied To “Infor-
mation Age” Inventions Like Digital 
Signal Processing, Because Such In-
ventions Operate On Data And Wave-
forms Rather Than Physical “Articles.” 
The  Bilski test limits patent-eligibility under its 
transformation prong to processes that transform 
“particular articles.” The word “article” carries with it 
sufficient industrial age baggage as to create con-
fusion in the contemporary information age. Because 
digital signals and data might not be regarded as 
“articles” due to their incorporeal nature, processes 
that operate on signals and data might now be 
excluded from patent-eligibility at the threshold.4 
This, Amici submit, would be error. 
4 In In re  Nuijten, 500 F.3d 1346 (Fed. Cir. 2007), the 
Federal Circuit traversed each of the categories enumerated in 
35 U.S.C. § 101 and found that an audio signal was neither a 
process, machine, manufacture or composition of matter and 
therefore such a signal did not itself qualify as patentable 
subject matter. In reaching this conclusion, the court made a 
determination that such a signal is not an “article.” The court 
reasoned that an “article” is “a particular substance or com-
modity” and further stated, in reliance on dictionary definitions: 
These definitions address “articles” of “manufacture” 
as being tangible articles or commoditiesA tran-
sient electric or electromagnetic transmission 
does not fit within that definition.  
(Continued on following page) 

Such technical inventions are fundamentally 
different from business methods and should remain 
patent-eligible. Digital audio signals, for example, are 
representations of disturbances of sound waves 
traveling through the air. Therefore, they represent 
something physical. When translated back into sound 
waves they impact human eardrums. They can be 
shaped and compressed much like the uncured rubber 
that was at issue in Diehr. Digital audio signal 
processing utilizes research in psychoacoustics to 
develop valuable processes for operating on, trans-
forming and synthesizing new digital audio signals. 
These processes epitomize the application of science 
to the creation or transformation of structures, and 
are a far cry from business methods that typically 
deal with human social relationships, legal obli-
gations and markets.  
In its attempt to rein in business methods, Bilski 
has created uncertainty as to the patentability of 
technology for processing audio waveforms and other 
similar inventions that are the focus of extensive 
investment in the contemporary information age. 
That the machine-or-transformation test effectively 
lumps together such inventions that represent the 
practical application of technical principles with 
business methods, demonstrates just how far astray 
the Federal Circuit has gone in Bilski
Id. at 1356 (emphasis added). Accordingly, the court concluded 
that audio signals lack the substance and tangibility requisite to 
being an article.  

B.  Bilski Admits Its Own Troubling Ambi-
The Bilski ruling expressly acknowledges the 
ambiguity that may result from applying its test in 
the realm of “information age” processes: 
[T]he main aspect of the transformation test 
that requires clarification here is what sorts 
of things constitute “articles” such that their 
transformation is sufficient to impart patent-
eligibility under § 101. It is virtually self-
evident that a process for a chemical or 
physical transformation of physical objects or 
substances is patent-eligible subject matter. . . . 
The raw materials of many information-
age processes, however, are electronic 
signals and electronically-manipulated 
data. And some so-called business methods, 
such as that claimed in the present case, 
involve the manipulation of even more 
abstract constructs such as legal obligations, 
organizational relationships, and business 
risks. Which, if any, of these processes 
qualify as a transformation or reduction 
of an article into a different state or 
thing constituting patent-eligible sub-
ject matter? 
See  Bilski, 545 F.3d at 962 (bold emphasis added). 
Bilski’s troubling ambivalence is even more apparent 
in its holding: 
[C]laim 1 does not involve the transforma-
tion of any physical object or substance, or 
an electronic signal representative of 

any physical object or substance. Given 
its admitted failure to meet the machine 
implementation part of the test as well, 
the claim entirely fails the machine-or-
transformation test and is not drawn to 
patent-eligible subject matter.  
Id.  at 964 (bold emphasis added). Thus, in Bilski 
itself, the Federal Circuit applied an expanded scope 
of the second prong of its test, one which, correctly, 
Amici contend, includes processes that transform “an 
electronic signal representative of any physical 
object or substance.” Id. (emphasis added). 
This prompts the question of whether the second 
prong of the test is limited to “articles” at all, whether 
signals and data are “actually articles,” or whether 
data and signals are not articles and may be excluded 
from patent-eligibility. What is clear is that 
technology companies should not have to bear the 
cross of Bilski’s uncertainty. Bilski’s ambivalent 
insertion of an industrial age “article” requirement 
within its test for patent-eligibility has done violence 
to the settled expectations of intellectual property 
leaders like the Amici and has established what 
amounts to bad economic policy. By narrowing and 
interjecting uncertainty into whether the trans-
formation and analysis of waveforms representing 
physical phenomena may be patentable, Bilski casts a 
cloud of uncertainty over such far-ranging technology 
fields as audio-visual compression and analytics, 
medical diagnostics, noise reduction and seismic 
analysis. Judge Newman in dissent in Bilski  was 

correct: “Uncertainty is the enemy of innovation.” Id. 
at 977. The uncertainty created by Bilski is neither 
required by precedent nor proper as a matter of 
C. Application  Of  Bilski Has Caused 
Serious Problems. 
Bilski’s machine-or-transformation test does not 
merely have the potential to cause confusion and 
doubt with respect to the patent-eligibility standard, 
it has actually caused such problems. For instance, 
the experience of the Amici has been that Examiners 
appear to be so uncomfortable with the vagueness of 
the transformation prong that they routinely reject 
all claims to digital audio coding processes that do not 
unambiguously satisfy the machine prong. For 
example, Dolby is currently pursuing patent appli-
cations containing process claims that explicitly recite 
innovative transformative operations on audio data. 
That the processes recited by these claims constitute 
practical applications of technological principles is 
beyond question. However, Examiners routinely hold 
that such claims are directed to nonstatutory subject 
matter. In particular, Examiners insist that patent-
eligibility can only be achieved by adding to the 
claims phrases such as “wherein X is implemented by 
a digital signal processor” or “wherein Y 
is performed by a computing device.” Based on 
these experiences, it appears that the machine-or-
transformation test has effectively reduced patent-
eligibility determinations within the Patent and 

Trademark Office to magic word expeditions, 
epitomizing the elevation of form over substance. 
D. The  Machine-or-Transformation  Test 
Elevates Form Over Substance. 
Due to its focus on very specific claim language 
characteristics, the machine-or-transformation test 
leads to the rejection of legitimate technical 
innovations that do not contain “magic words” and 
the allowance of claims for non-technical processes 
that do.  
Any claim, even one for a business method or an 
abstract idea, could be formulated to comply with the 
machine-or-transformation  test with clever drafts-
manship. For example, if the phrase “wherein the 
method is performed by a computing device” is added, 
the claim may pass muster under the U.S. Patent 
Office’s current application of the machine-or-
transformation test. 
Bilski decision, it would generally 
have been considered bad practice to recite specific 
hardware in a claim to a method that is hardware-
independent, or to recite what is represented by data 
in a claim to a method that is content-independent. 
Consequently, adopting the machine-or-transformation 
requirement at this point may retroactively 
invalidate innumerable already-issued claims to 
legitimate technological innovations. 

A. Under  Diehr’s Holding, The Only 
Exclusions From Patent-Eligibility Are 
“Laws Of Nature, Natural Phenomena, 
And Abstract Ideas.” 
The machine-or-transformation test, like other 
now-abandoned patent-eligibility tests that came 
before it, purports to be rooted in the policies 
articulated in Diamond v. Diehr, 450 U.S. 175 (1981). 
The  Diehr  standard, however, was not so constricted 
as to limit patent-eligibility to processes that are “tied 
to a particular machine” or transform a “particular 
Diehr took a broad view of what constitutes a 
“process” and imported no extrinsic limitations to 
Section 101’s pronouncement that processes are 
patentable. The Court noted that Section 101 imposes 
no restrictions on process patentability other than 
that the process be new and useful. Diehr, 450 U.S. at 
183 (citing Cochrane v. Deener, 94 U.S. 780, 787-88 
(1876) (“If new and useful, [a process] is just as 
patentable as is a piece of machinery.”)); see also 35 
U.S.C. § 101. The Court further noted that “Congress 
intended statutory subject matter to include anything 
under the sun that is made by man.” Diehr, 450 U.S. 
at 182 (citation omitted). 
Diehr, where a process was transformative, its 
eligibility for patenting was “not altered by the fact 
that in several steps of the process a mathematical 

equation and a programmed digital computer are 
used.” Id. at 185.5 To the contrary, the Court held that 
“a process may be patentable, irrespective of the 
particular form of the instrumentalities used. . . .” Id. 
at 182-83 (citation omitted).  
Diehr was a culmination of the Court’s maturing 
views on computer software patenting that began 
first with Gottschalk v. Benson, 409 U.S. 63 (1972) 
and then Parker v. Flook, 437 U.S. 584 (1978). In both 
Benson and Flook, claims were ineligible for patenting 
because the applicants claimed what the Court be-
lieved to be nothing more than abstract mathematical 
formulas that were “like laws of nature.”6 
Diehr  represented the inverse  proposition – a 
process that applied a mathematical formula could 
5  Significantly, the process at issue in Diehr differed from 
the prior art only with respect to steps performed internal to the 
general purpose digital computer involved in the rubber-curing 
process. The Diehr Court’s allowance of such claims clearly 
signaled that an applicant may be entitled to patent protection 
even when the inventor’s contribution to the art occurs entirely 
within a computing device. 
6 In  Flook, the Court analogized such formulas to the 
Pythagorean theorem. Flook, 437 U.S. at 590. In Diehr, the 
Court analogized such formulas to Einstein’s equation E=mc2 
and Newton’s law of gravity. Diehr, 450 U.S. at 185. From these 
analogies, it is clear that the Court intended the exclusion to 
cover only formulas that mathematically represent laws of 
nature. However, in the context of computer-implemented 
processes, such as digital signal processing, many “formulas” are 
based entirely on human ingenuity and not natural laws, and 
are therefore not “like laws of nature.” 

be patentable  where the result was practical, 
allowing a claim to an improved curing process for 
rubber that used the Arrhenius equation. So long as 
the equation was practically applied, the process that 
used the equation fell outside of the narrow 
exclusions set forth in Benson  and  Flook.  The Court 
It is now commonplace that an application of 
a law of nature or mathematical formula to a 
known structure or process may well be 
deserving of patent protection. (Internal 
citations omitted). As Justice Stone ex-
plained four decades ago: “While a scientific 
truth, or the mathematical expression of it, 
is not a patentable invention, a novel and 
useful structure created with the aid of 
knowledge of scientific truth may be.” 
(quoting  Mackay Radio & Telegraph Co. v. 
Radio Corp. of America, 306 U.S. 86, 94 
Diehr, 450 U.S. at 187-88 (emphasis in original). 
Thus,  Diehr held that using mathematical steps is 
not anathema to patent-eligibility where a practical 
result follows from the application of such principles. 
After  Diehr, only “laws of nature, natural phe-
nomena, and abstract ideas” are patent-ineligible. 
Diehr, 450 U.S. at 185.7 Because of this holding, Diehr 
7  Diehr  confirmed that Benson and Flook stand for “no 
more” than the exclusion of those three categories from patent-
eligibility. Id. at 185-86 (emphasis added). 

represented a starting point for future invention in 
the realm of computer and information technology. It 
was not a cage with which to contain the 
contemporary information age. 
B.  Diehr’s Practical Application Require-
ment Did Not Require Transformation 
Of Physical “Articles.” 
Diehr  held only that claims to a practical 
application – internal mathematical operations 
notwithstanding – are separate and apart from the 
sort of abstract patent-ineligible claims in Benson and 
Flook.8 The Bilski Court placed too much emphasis on 
Diehr’s use of the term “article” in the statement: 
“Transformation and reduction of an article ‘to a 
different state or thing’ is the clue to the patentability 
of a process claim that does not include particular 
machines.”  Diehr, 450 U.S. at 184 (citation omitted). 
8 In 1994, the Federal Circuit illustrated a clear under-
standing of this distinction when it stated: 
[T]he proper inquiry in dealing with the so called 
mathematical subject matter exception to § 
alleged herein is to see whether the claimed subject 
matter  as a whole is a disembodied mathematical 
concept, whether categorized as a mathematical 
formula, mathematical equation, mathematical 
algorithm, or the like, which in essence represents 
nothing more than a ‘law of nature,’ ‘natural 
phenomenon,’ or ‘abstract idea.’ If so, Diehr precludes 
the patenting of that subject matter. 
In re Alappat, 33 F.3d 1526, 1544 (Fed. Cir. 1994, en banc
(emphasis in original). 

Diehr  found that even a process with mathematical 
elements could be patent-eligible where as a whole 
the claim is drawn to some practical application; 
thus,  Diehr was concerned with the practical appli-
cations produced by the steps in a transformative 
process, not the nature of the objects in those steps. 
The Court did not in any way limit what the objects 
of such patent-eligible applications could be. Nor did 
it need to in order to harmonize Benson and Flook.  
Quite to the contrary, the Diehr opinion oscillates 
between the use of the term “article” – which has 
connotations of tangibility and physicality  – and the 
use of the term “structure” – which is broader. 
Further,  Diehr did not limit patentability to 
transformation of physical articles, but noted only 
that “articles” are just examples of something that 
patent-eligible processes might transform. Diehr, 450 
U.S. at 192 (“On the other hand, when a claim 
containing a mathematical formula implements or 
applies that formula in a structure or process which, 
when considered as a whole, is performing a function 
which the patent laws were designed to protect (e.g.
transforming or reducing an article to a different 
state or thing), then the claim satisfies the require-
ments of § 101”).  
By imposing the requirement that an article 
must be transformed to be patentable, Bilski  runs 
counter to Diehr’s express prohibition against 
narrowing the scope of patent-eligibility:  

. . . in dealing with the patent laws, we have 
more than once cautioned that “courts should 
not read into the patent laws limitations and 
conditions which the legislature has not 
Id. at 182 (quoting  Diamond v.  Chakrabarty, 447 
U.S. 303, 308 (1980)) (internal quotation omitted). 
Unfortunately, these warnings have largely gone 
unheeded.9 The judicial history of Section 101 
illustrates a repeated cycle in which lower courts 
have used statements from BensonFlook, and Diehr 
as the basis for patent-eligibility tests that go beyond 
those “long-established principles,” only later to 
abandon those tests when it becomes evident that 
they exclude subject matter that the patent system 
was clearly intended to cover.10 The establishment of 
9  In re Alappat, 33 F.3d 1526, 1543 (Fed. Cir. 1994, en banc
stands as a noteworthy exception. The Alappat Court recognized 
A close analysis of Diehr, Flook, and Benson reveals 
that the Supreme Court never intended to create an 
overly broad, fourth category of subject matter 
excluded from § 101. Rather, at the core of the Court’s 
analysis in each of these cases lies an attempt by the 
Court to explain a rather straightforward concept, 
namely, that certain types of mathematical subject 
matter, standing alone, represent nothing more than 
abstract ideas until reduced to some type of 
practical application, and thus that subject matter 
is not, in and of itself, entitled to patent protection. 
(Bold emphasis added). 
10  See,  e.g.,  Bilski, 545 F.3d at 959 (“we conclude that the 
Freeman-Walter-Abele test is inadequate”), and Bilski, at 959-60 
(Continued on following page) 

a machine-or-transformation test by the Federal 
Circuit in Bilski is merely the latest iteration of that 
cycle. Similar to each of its predecessor tests, that 
test excludes a wide range of legitimate technological 
innovations, and accordingly should be discarded. 
A. Decades Of Post-Diehr Federal Circuit 
Precedent Confirm That Data And 
Waveform Transformation, Including 
Practical Applications of Digital Sig-
nal Processing, Are Properly Patent-
The principles set forth in Diehr regarding 
patentable subject matter under Section 101 have 
proven to be just as applicable to contemporary 
information technology as they were to the computer-
aided industrial rubber curing process Diehr 
specifically addressed. Three decades of post-Diehr 
precedent confirm that practical applications of 
digital signal processing and other methods that 
operate on incorporeal forms of data are still entitled 
to patent protection.  
In re Abele, 684 F.2d 902 (Cust. & Pat. App. 
1982), the predecessor court to the Federal Circuit 
Court of Appeals reviewed “an improvement in CAT 
(“we also conclude that the ‘useful, concrete and tangible result’ 
inquiry is inadequate”). 

scan imaging technique whereby the body [was] 
exposed to less radiation and, through use of a 
weighting function in the calculations producing 
the image, the artifacts [were] eliminated.” Id. at 
904. Although an independent claim drawn to a 
mathematical algorithm without regard to the data 
source was found not to be patent-eligible, the court 
did find that a dependent claim tied to “X-ray 
attenuation data” was patentable. Id. at 908-09. The 
dependent claim did not recite “a mere procedure for 
solving a given mathematical problem.” Id. at 909. 
Rather, like in Diehr, the improvement “reside[d] in 
the application of a mathematical formula within the 
context of a process which encompasse[d] signif-
icantly more than the algorithm alone.” Id.11 
Arrhythmia Research Tech., Inc. v. Corazonix 
Corp., 958 F.2d 1053 (Fed. Cir. 1992), the Federal 
Circuit held that a mathematical analysis of a digital 
representation of an echocardiographic heart reading 
that could identify an acute arrhythmia was 
patentable. The court found that though there was a 
mathematical aspect to the invention, the “input 
signals . . . [were] related to the patient’s heart 
function,” the transformation of electrical signals 
11 In discussing Abele, the Federal Circuit suggested that 
the patent-eligible claim recognized a sufficient nexus to the 
physical world, noting that the “data clearly represented 
physical and tangible objects, namely the structure of bones, 
organs, and other body tissues.” See Bilski, 545 F.3d at 963 
(discussing Abele). 

from one form to another was itself physical, and 
ultimately “a signal related to the patient’s heart 
activity,” something manifestly physical, was the 
“resultant output.” Id. at 1059 (emphasis added). The 
court expressly noted the analogy to Diehr, stating 
“applicants ‘do not seek to patent a mathematical 
formula . . . they seek only to foreclose from others 
the use of that equation in conjunction with all of the 
other steps in their claimed process.’ ” Id. at 1059-60. 
The same sort of physicality relied on in Arrhythmia 
is found in digital audio signals. Audio signals relate 
to sound waves that travel through the air which 
when incident on the human ear drum create the 
perception of sound. They are analogous to the 
echocardiographic signals that measured heart rate, 
which were analyzed in Arrhythmia  and held to be 
In re Nuijten, 500 F.3d 1346, 1356-57 (Fed. Cir. 
2007) confirmed patent-eligibility of a process for 
embedding a digital watermark in a digital audio 
signal without comment. Claim 1 of the Nuijten 
application, which was not at issue but was 
mentioned by the Federal Circuit, illustrates just how 
well-entrenched digital audio signal processing has 
become as a patent-eligible field.12 This process claim 
12  Claim 1 is the broadest process claim allowed. It reads: 
A method of embedding supplemental data in a signal, 
comprising the steps of: 
encoding the signal in accordance with an 
encoding process which includes the step of 
(Continued on following page) 

is not tied to a “particular machine” and it operates 
on nothing more than an audio “signal” to improve its 
quality. A Bilski footnote commented, “[w]e note 
that the PTO did not dispute that the process 
claims in Nuijten were drawn to patent-eligible 
subject matter under § 101 and allowed those 
claims.”  Bilski,  545 F.3d at 951, n.2 (bold emphasis 
added). Though these claims were allowed by the 
Patent Office, and were not criticized in Bilski, there 
is more than a mere hypothetical concern that such 
claims would not be deemed patent-eligible post-
Bilski. See Section IC, supra (post-Bilski, the PTO is 
requiring machine references which wrongfully limit 
the scope of the invention). 
Diehr allows claims that apply mathematical, 
scientific or technological principles to achieve a 
practical result. This strikes an appropriate balance 
between society’s interest in creating incentives for 
companies to invest in research and development 
versus the need to preserve fundamental principles, 
feeding back the encoded signal to control 
the encoding; and modifying selected sam-
ples of the encoded signal to represent the 
supplemental data prior to the feedback of 
the encoded signal and including the mod-
ifying of at least one further sample of 
the encoded signal preceding the selected 
sample if the further sample modification is 
found to improve the quality of the en-
coding process. 
Nuijten, 500 F.3d at 1351.  

abstract ideas and general scientific knowledge to the 
public. It should be as effective going forward as it 
has been since it was instituted three decades ago. 
B. If Bilski’s Invention Is To Be Rejected 
Based On The Non-Technical Nature 
Of The Invention, The Standard 
Applied Should Be Precise And 
The claimed invention in Bilski  is a method of 
hedging risks in commodities trading. The Amici take 
no position on whether the Bilski claims should be 
rejected. If, however, patentability is rejected based 
on the non-technical nature of the invention,13 the 
standard should be articulated with sufficient pre-
cision as to leave no ambiguity that processes 
practically applying scientific and mathematical 
technological principles remain patent-eligible.  
----------------- ♦ ----------------- 
This Court’s jurisprudence in Diehr provides an 
appropriate roadmap for patentability into the 21st 
Century. Under Diehr, the manipulation of a 
waveform by application of scientific principles to 
achieve a result that has practical use is patentable. 
Not only does such a test provide certainty and 
13  See Article I, Section 8 of the U.S. Constitution.  

consistency with prior precedent, it is proper policy as 
well. Furthermore, this Court should not hold that 
patentability requires the transformation of material 
or an “article” with the traditional physicality of the 
industrial age. Such an interpretation would do 
violence to innumerable technological innovations 
that have useful, practical application in the infor-
mation age. 
Respectfully submitted, 
235 Montgomery Street 
San Francisco, CA 94105 
(415) 954-4400 
Counsel of Record for Amici 
  DTS, Inc., and SRS Labs, Inc. 
2055 Gateway Place, Ste. 550 
San Jose, CA 95110 
(408) 414-1080 
Of Counsel to Dolby Laboratories 
100 Potrero Street 
San Francisco, CA 94103 
(415) 558-0200 
Of Counsel to Dolby Laboratories 

5171 Clareton Drive 
Agoura Hills, CA 91301 
(818) 827-2200 
Of Counsel to DTS, Inc.  
2040 Main Street, Ste. 1400  
Irvine, CA 92614 
(949) 721-2998 
Of Counsel to SRS Labs, Inc. 

Document Outline