Ex Parte Derti et al

Patent Trial and Appeal Board

Sep 30, 2014

11522740 (P.T.A.B. Sep. 30, 2014)

UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE PATENT TRIAL AND APPEAL BOARD
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Ex parte GZIM DERTI, CARL R. HOLMQVIST,
and HAROLD J. WILSON
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Appeal 2012-007087
Application 11/522,740
Technology Center 2600
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Before CARLA M. KRIVAK, ELENI MANTIS MERCADER, and
DANIEL J. GALLIGAN, Administrative Patent Judges.

MANTIS MERCADER, Administrative Patent Judge.

DECISION ON APPEAL

Appeal 2012-007087
Application 11/522,740

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STATEMENT OF THE CASE
Appellants appeal under 35 U.S.C. § 134(a) from a final rejection of
claims 1–20. We have jurisdiction under 35 U.S.C. § 6(b).
We reverse.

THE INVENTION
Appellants’ claimed invention is directed to modeling signal delays in
a metastability protection circuit. A metastability protection circuit
processes a signal that crosses between two clock domains modeled by
introducing a random transition delay into the signal upon detection of an
edge in the signal. Abstract.
Independent claim 1, reproduced below, is illustrative of the subject
matter on appeal.
1. A method for simulating a metastability protection circuit
that processes a signal that crosses between two clock domains,
comprising:
generating a random value R; and
introducing a random transition delay into said signal
upon detection of an edge in said signal by assigning said
random value R to said signal, wherein said introduction step is
performed by a processor.

REFERENCES and REJECTIONS
1. The Examiner rejected claims 1, 7, 8, 14, and 15 under 35 U.S.C.
§ 103(a) as being unpatentable over Marmash (US 7,382,824 B1, June
3, 2008).
2. The Examiner rejected claims 2, 4, 5, 9, 11, 12, 16, 18, and 19 under
35 U.S.C. § 103(a) as being unpatentable over Marmash and Lee (US
7,289,946 B1, Oct. 30, 2007).
Appeal 2012-007087
Application 11/522,740

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3. The Examiner rejected claims 3, 6, 10, 13, 17, and 20 under 35 U.S.C.
§ 103(a) as being unpatentable over Marmash and Swapp (US
5,020,038, May 28, 1991).

ISSUE
The issue is whether the Examiner erred in finding Marmash teaches
“introducing a random transition delay into said signal upon detection of an
edge in said signal,” as recited in claim 1 and similarly recited in
independent claims 8 and 15.

ANALYSIS
Claims 1, 7, 8, 14 and 15
Appellants argue inter alia that Marmash does not teach or suggest
“introducing a random transition delay into said signal upon detection of an
edge in said signal” (emphasis added) (App. Br. 4–5). In particular,
Appellants argue Marmash introduces a delay into a signal via flip-flop
(F/F) Stages 1-3 before the detection of an edge (App. Br. 4).
We agree with Appellants’ argument. As shown in Marmash’s Figure
1, the delays introduced by the three-stage delay network 16 into a signal are
introduced via F/F stages 1-3 before the detection of an edge by the edge
detector 24.
Thus, we reverse the Examiner’s rejection of claim 1 and for the same
reasons, the rejections of claims 8 and 25.
Appeal 2012-007087
Application 11/522,740

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Claims 2-6, 9-13, and 16-20
We also reverse the Examiner’s rejections of claims 2–6, 9–13, and
16–20 for the same reasons as stated supra. The additional references of
Lee and Swapp do not cure the above-cited deficiencies.
CONCLUSION
The Examiner erred in finding Marmash teaches “introducing a
random transition delay into said signal upon detection of an edge in said
signal” as recited in claim 1 and similarly recited in independent claims 8
and 15.

DECISION
The Examiner’s decision rejecting claims 1–20 is reversed.

REVERSED

msc