Anticipate This!™ | Patent and Trademark Law Blog

In Re Petrus A.C.M. Nuijten.

Posted in Opinion Commentary by Jake Ward on September 25, 2007

A “signal” is not patentable subject matter because it is not a tangible article or commodity. 

(Fed. Cir. 2007, 06-1371)


The issue before the CAFC was whether or not a signal is patentable subject matter?  Nuijten appealed a decision of the BPAI that maintained a rejection of his claims reciting a “signal” encoded in a particular manner.  The CAFC affirmed.

The technology at issue relates to a technique for reducing distortion induced by the introduction of “watermarks” into signals.  The Nuijten technique improved upon existing watermark technology by modifying the watermarked signal in a way that partially compensated for distortion introduced by the watermark.  Claim 14 at issue recites:

A signal with embedded supplemental data, the signal being encoded in accordance with a given encoding process and selected samples of the signal representing the supplemental data, and at least one of the samples preceding the selected samples is different from the sample corresponding to the given encoding process.

In first construing the term “signal,” the CAFC determined that a signal is more than just data.  Some physical form for the signal is required – but the nature of the physical carrier is totally irrelevant to the issue of whether the signal constitutes statutory subject matter.  Instead, the appropriate inquiry was whether a transitory propagating signal is within any of the four statutory categories:  process, machine, manufacture, or composition of matter?  The CAFC addressed these categories as follows.

1) Process

The Supreme Court and this court have consistently interpreted the statutory term “process” to require action.  A process consists of doing something, and therefore has to be carried out or performed.  Nuijten noted that the claimed signal must be “encoded in accordance with a given encoding process.” However, the presence of acts recited in the claim does not transform a claim covering a thing—the signal itself—into one covering the process by which that thing was made.  The signal claims are not directed to a process.

2)  Machine

The Supreme Court has defined the term “machine” as “a concrete thing, consisting of parts, or of certain devices and combination of devices.” A transitory signal made of electrical or electromagnetic variances is not made of “parts” or “devices” in any mechanical sense. While such a signal is physical and real, it does not possess concrete structure in the sense implied by these definitions. A signal is clearly not a machine.

3)  Manufacture

The majority noted that this statutory category was the most difficult to analyze here.  Articles of manufacture are man-made, in the sense of having been encoded, generated, and transmitted by artificial means. However, artificiality is insufficient by itself to render something a “manufacture.” Under the statutory use of the term “manufacture” and dictionary definitions, “articles” of “manufacture” are defined as tangible articles or commodities.  A transient electric or electromagnetic transmission does not fit within that definition.

4)  Composition of matter

The Supreme Court has defined “composition of matter” to mean “all compositions of two or more substances and all composite articles.”  A signal comprising a fluctuation in electric potential or in electromagnetic fields is not a “composition[s] of matter.”

Accordingly, the CAFC held that a transitory, propagating signal cannot be patentable subject matter. 


Judge Linn dissented-in-part, arguing that the definition of a “manufacture” should not be limited to tangible, non-transitory things.  Instead, under an expansive view of the term “manufacture,” the dissent would hold that a signal that is a non-naturally occurring product of human ingenuity is patentable subject matter if it is otherwise new, useful, and non-obvious.

3 Responses

Subscribe to comments with RSS.

  1. Deborah MacPherson said, on March 8, 2008 at 12:05 pm

    RE: transitory, propagating signal ~ in your opinion do you think a continuous propagating signal would constitute patentable subject matter?

  2. Jake Ward said, on March 8, 2008 at 12:19 pm

    Based on the Nuijten holding, I rather doubt the court would find any type of “signal” not tied to a physical medium to fall under the four statutory categories. A signal is not tangible, and thus would not fall under the article of manufacture category (the closest category in this case). Being artificial, under Nuijten anways, is not enough. Maybe there is some distinction between a transitory and a continuous propogating signal that I am not fully appreciating, however?

    The courts appear to be swinging back to a narrower view than has been held in recent memory of what constitutes patentable subject matter. This is why the Bilski en banc hearing (directed to so-called business method patents) is of such interest to practitioners. See .

  3. said, on July 24, 2008 at 5:21 pm

    See the analysis comments.

    The physical mechanisms, when dependent on specific physical constraints, can be claimed as a mechanism of action, however their act and the result of their act in a non physical system can not be verified for patent.

    A chip core, like intel, is a signal modifier with tangible physical, interprtetation of process within it is not relevant, and the same non-physical systems (or structures different in physical design doingthe same thing) such as resulting signals are not a patentable result.

    Mechanisms of operating a car physical, not the concept of a car.

    A physical system COULD be a claim, but in no way could that specific limitation or dtesign effect implementation with other physical designs.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: