Ex Parte HELLUMS et al

Board of Patent Appeals and Interferences

Jul 15, 2003

09103704 (B.P.A.I. Jul. 15, 2003)

-1-
The opinion in support of the decision being entered
today was not written for publication in a law journal
and is not binding precedent of the Board.
Paper No. 15
UNITED STATES PATENT AND TRADEMARK OFFICE

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES

Ex parte JAMES R. HELLUMS and JAMES R. HOCHSCHILD

Appeal No. 2001-2694
Application No. 09/103,704

ON BRIEF

Before KRASS, BARRETT and RUGGIERO, Administrative Patent Judges.
KRASS, Administrative Patent Judge.
DECISION ON APPEAL
This is a decision on appeal from the final rejection of
claims 1-9 and 13.
The invention pertains to a time domain noise analyzer. In
particular, a simulator comprises a matrix of electrical circuit
elements and an analyzer for analyzing transient responses of the
circuit elements in the time domain with a known input signal to
provide a deterministic current value for each of the elements.
A noise source is associated with each circuit element for
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generating a noise current for the associated element,
representing a white noise that exists within the element. The
generated noise current for each noise source is summed with the
deterministic current value for each element and the matrix of
elements is solved after performing all of the summing
operations.
Representative independent claim 1 is reproduced as follows:
1. A simulator for simulating the noise response of an
electrical circuit in the time domain, which simulator operates
in discrete time steps Ts, comprising:
a matrix of electrical circuit elements representing the
electrical circuit;
an analyzer for analyzing the transient response of the
circuit elements in the matrix in the time domain with a known
input signal to provide a deterministic current value for each of
said elements operating in the electrical circuit;
a stochastic noise source associated with each of said
elements, each for generating a noise current for the associated
element that represents a stochastic random process comprised of
a white noise source scaled by the standard deviation of the
physical noise process that exists within said associated
element;
a primary summing device is associated with each of said
elements for summing the generated noise current for the
associated one of said stochastic noise sources with the
deterministic current values associated with each of said
elements; and
a matrix solver for solving the matrix after said summing
device has performed the associated summing operation.
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The examiner relies on the following references:
P. Bolcato et al. (Bolcato), "A new approach for Noise simulation
in transient analysis," 2 IEEE International Symposium on
Circuits and Systems 887-90 (1992)
N. Jeremy Kasdin, "Discrete Simulation of Colored Noise and
Stochastic Processes and 1/f
Power Law Noise Generation,"
83 Proceedings of the IEEE no. 5, 802-27 (May 1995)
Serban-Mihai Popescu et al. (Popescu), "A Noise Modelling
Approach for Accurate Time Domain Analysis," IEEE International
Semiconductor Conference 553-56 (1996)
Claims 1-9 and 13 stand rejected under 35 U.S.C. § 103. As
evidence of obviousness, the examiner offers Popescu and Bolcato
with regard to claims 1-4 and 13, adding Kasdin with regard to
claims 5-9.
Reference is made to the brief and answer for the respective
positions of appellants and the examiner.
OPINION
In rejecting claims under 35 U.S.C. § 103, it is incumbent
upon the examiner to establish a factual basis to support the
legal conclusion of obviousness. See In re Fine, 837 F.2d 1071,
1073, 5 USPQ2d 1596, 1598 (Fed. Cir. 1988). In so doing, the
examiner is expected to make the factual determinations set forth
in Graham v, John Deere Co., 383 U.S. 1, 17, 148 USPQ 459, 467
(1966), and to provide a reason why one having ordinary skill in
the pertinent art would have been led to modify the prior art or
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to combine prior art references to arrive at the claimed
invention. Such reason much stem from some teachings,
suggestions or implications in the prior art as a whole or
knowledge generally available to one having ordinary skill in the
art. Uniroyal, Inc. v. Rudkin-Wiley Corp., 837 F.2d 1044, 1051,
5 USPQ2d 1434, 1438 (Fed. Cir.), cert. denied, 488 U.S. 825
(1988); Ashland Oil, Inc. v. Delta Resins & Refractories, Inc. ,
776 F.2d 281, 293, 227 USPQ 657, 664 (Fed. Cir. 1985), cert.
denied, 475 U.S. 1017 (1986); ACS Hosp. Sys., Inc. v. Montefiore
Hosp., 732 F.2d 1572, 1577, 221 USPQ 929, 933 (Fed. Cir. 1984).
These showings by the examiner are an essential part of complying
with the burden of presenting a prima facie case of obviousness.
Note In re Oetiker, 977 F.2d 1443, 1445, 24 USPQ2d 1443, 1444
(Fed. Cir. 1992). If that burden is met, the burden then shifts
to the applicant to overcome the prima facie case with argument
and/or evidence. Obviousness is then determined on the basis of
the evidence as a whole and the relative persuasiveness of the
arguments. See Id.; In re Hedges, 783 F.2d 1038, 1040, 228 USPQ
685, 687 (Fed. Cir. 1986); In re Piasecki, 745 F.2d 1468, 1472,
223 USPQ 785, 788 (Fed. Cir. 1984); and In re Rinehart, 531 F.2d
1048, 1051, 189 USPQ 143, 146-47 (CCPA 1976). Only those
arguments actually made by appellants have been considered in
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this decision. Arguments which appellants could have made but
chose not to make in the brief have not been considered and are
deemed to be waived (see 37 CFR 1.192 (a)).
The examiner applies Popescu for a teaching of transient
noise analysis through simulation in the time domain of a circuit
and the generation of stationary noise. Recognizing that Popescu
does not teach the generation of noise for each circuit element
represented in the simulation, the examiner turns to Bolcato for
a teaching of added current sources as representing physical
noises of devices. The examiner concludes that it would have
been obvious “to incorporate the noise equivalent current sources
of Bolcato . . . into the noise simulation methods disclosed by
Popescu . . ., because such a combination would permit more
accurate noise modelling using a SPICE-type simulator” (answer,
page 5).
For their part, appellants argue that whereas independent
claims 1 and 13 require a noise source for each circuit element
and a summing of the element’s noise current with the element’s
deterministic current, “Popescu simulates with a single noise
source for an entire circuit and, in fact, adds the precomputed
noise after generating the circuit output (page 554, second and
fourth paragraphs of section 2)” (brief, page 3).
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Moreover, argue appellants, Bolcato does not provide for the
deficiency of Popescu because Bolcato injects a deterministic
current source for each noisy element with the frequencies and
amplitudes picked to emulate a physical noise spectrum, then
performs N + 1 simulation runs, first without the current sources
and then N times using the current sources with the phases of the
sinusoids varied between runs, citing page 889, left column.
Thus, appellants contend, Bolcato has no noise generation during
a simulation run but, rather, current source phase increments at
the beginning of each simulation run (see brief-page 3).
Appellants conclude that “Bolcato does not suggest putting a
noise source with each circuit element for simulation in Popescu
because Bolcato really does not use noise sources (i.e.,
something that is random during a simulation run). In fact,
Bolcato page 888, right column, fourth paragraphs of section A)
specifically avoids them” (brief, pages 3-4).
The examiner’s response is to agree with appellants that
Popescu teaches a circuit simulation using a single noise source
for an entire circuit. However, pointing to the same portion of
Popescu as do appellants (page 554, section 2), the examiner
argues that Popescu does not add precomputed noise after
generating the circuit output and that Popescu, in fact, adds the
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noise signal during the simulation in either a time-voltage or a
time-current pair corresponding to appellants’ “summing device.”
The examiner further points out, again, that Bolcato teaches
adding noise sources in parallel and relies on the desirability
of replacing circuit elements in a simulation with corresponding
circuit elements having added noise sources in parallel. It is
the examiner’s position that such a set of noise sources in
parallel, if added to Popescu’s system “would then include a
stochastic noise source associated with each circuit element that
would add the generated noise current with the deterministic
current values associated with each circuit element” (answer,
pages 7-8), concluding that a “simulation using [sic] made by the
system of Popescu with noise elements added in parallel as
illustrated by Bolcato would have increased accuracy and would
better model the noise process in an actual circuit” (answer,
page 8).
After reviewing the references and the arguments by
appellants and the examiner, we will not sustain the rejection of
claims 1-9 and 13 under 35 U.S.C. § 103 because it is simply not
clear to us that the references disclose what the examiner
contends they disclose.
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We have specifically reviewed page 554 of Popescu which both
appellants and the examiner rely on to support their respective
positions regarding whether Popescu adds the noise signal during
the simulation. While Popescu does disclose that noise traces
are saved in files in a form of time-voltage or time-current
pairs and “fed at the simulator inputs . . .,” possibly arguing
for adding noise signals during simulation, the reference, on the
same page, indicates that “we shifted the noise generator away
from the simulation tool,” appearing to indicate that the noise
signal is not added during simulation which is clearly required
by the instant claims.
In summary, since we must resort to some speculation as to
whether Popescu is generating a noise current during simulation,
we will not sustain the examiner’s rejection of the claims
because a rejection under 35 U.S.C. § 103 may not be based on
speculation as to what a reference discloses.
Moreover, while Bolcato does appear to disclose the
introduction of current sources in each noisy component (page
888, left-hand column), we are not convinced that the artisan
would have been led by this teaching to include such a current
source in each element in Popescu for generating a noise current
for an associated element in a simulator if it is unclear whether
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Popescu even discloses the addition of a noise signal during
simulation. Kasdin, added for other reasons related to
claims 5-9, does nothing to provide for the deficiencies of
Popescu and Bolcato.
In short, while the examiner has clearly cited very relevant
references, we are not convinced, by the examiner’s rationale,
that the combination of these references would have made the
instant claimed subject matter obvious, within the meaning of
35 U.S.C. § 103.
Perhaps the examiner could have made a stronger case by
going through each claimed element, one-by-one, and explaining
how each element is considered to correspond to a specific
teaching of the references. The examiner made only general
statements about the teachings of the references without clearly
pointing out, where, in the references, for example, the
“matrix,” the “analyzer” and the “matrix solver” are considered
to be taught. Accordingly, we find that the examiner has simply
not established a prima facie case of obviousness. While
appellants do not argue each and every claimed element and while
some of their arguments appear weak, it is the examiner, in the
first instance, who must show a reasonable case that each and
every claimed element, taken as a whole, is taught, or made
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obvious, by the applied references, i.e., the examiner has the
initial burden to establish a prima facie case of obviousness
with regard to the claimed subject matter. Since the examiner
has not set forth a convincing case for obviousness, the burden
of showing nonobviousness never shifted to appellants.
The examiner’s decision rejecting claims 1-9 and 13 under
35 U.S.C. § 103 is reversed.
REVERSED
ERROL A. KRASS )
Administrative Patent Judge )
)
)
)
)
LEE E. BARRETT ) BOARD OF PATENT
Administrative Patent Judge ) APPEALS AND
) INTERFERENCES
)
)
)
JOSEPH F. RUGGIERO )
Administrative Patent Judge )
EAK:clm
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Texas Instruments Inc.
P.O. Box 655474, M/S 3999
Dallas, TX 75265