Ex Parte Eiselt et al

Patent Trial and Appeal Board

Dec 31, 2012

10427210 (P.T.A.B. Dec. 31, 2012)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________________

Ex parte MICHAEL H. EISELT, LARA DENISE GARRETT
and MARK SHTAIF
____________________

Appeal 2010-000349
Application 10/427,2101
Technology Center 2600
____________________

Before JOSEPH L. DIXON, ST. JOHN COURTENAY III, and
MARC S. HOFF, Administrative Patent Judges.

HOFF, Administrative Patent Judge.

DECISION ON APPEAL

STATEMENT OF THE CASE
Appellants appeal under 35 U.S.C. § 134 from a Final Rejection of
claims 1, 2, 4-21, and 26-36.2 We have jurisdiction under 35 U.S.C. § 6(b).
We reverse.

1 The real party in interest is Pivotal Decisions L.L.C.
2 Claims 3 and 22-25 have been cancelled.
Appeal 2010-000349
Application 10/427,210

2
Appellants’ invention is an optical fiber transport system using return-
to-zero (RZ) signal modulation. The inventive system uses a filter with a
3dB bandwidth between about 0.4 and 0.6 times the bit rate, in order to
achieve optimum electrical receiver bandwidth (Spec. 2).
Claim 1 is exemplary of the claims on appeal:
1. An optical transport system comprising:
a laser transmitter configured to produce an optical signal;
a modulator module optically coupled to the laser transmitter, wherein
the modulator module is configured to modulate the optical signal in a
return-to-zero format; and
a receiver module optically coupled to the modulator module, wherein
the receiver module is configured to receive and convert the optical
signal into an electrical signal, and wherein the receiver module is
further configured to filter noise from the electrical signal at a 3dB
bandwidth between about 0.4 to 0.6 times a bit rate to optimize a
signal-to-noise ratio of the receiver module.

The Examiner relies upon the following prior art in rejecting the
claims on appeal:
Kurchuk US 2002/0101641 A1 Aug. 1, 2002
Rosencwaig US 6,781,692 B1 Aug. 24, 2004

M. M. Strasser3 et al. Experimental verification of optimum filter
bandwidths in direct-detection (N)RZ receivers limited by optical noise. The
14th Annual Meeting of the IEEE. November 2001, Lasers and Electro-Optics
Society 2, 485-486 (2001)

Claims 1, 2, 4, 6, 15, 26, 27, 29, 30, 34, and 35 stand rejected under
35 U.S.C. § 103(a) as being unpatentable over Strasser.
Claims 5, 7, 8, 10-14, 16-21, 31-33, and 36 stand rejected under 35
U.S.C. § 103(a) as being unpatentable over Strasser in view of Kurchuk.

3 The Examiner refers to this reference as “Winzer.”
Appeal 2010-000349
Application 10/427,210

3
Claims 9 and 28 stand rejected under Strasser in view of Rosencwaig.

ISSUES
Appellants argue, inter alia, that the Examiner erred in concluding
that modifying Strasser’s receiver module to filter noise at a 3dB bandwidth
between about 0.4 to 0.6 times a bit rate would have been obvious as a
matter of discovering the optimum or workable ranges for a specific system
using routine skill in the art (App. Br. 6-7). Appellants assert that Strasser
contains no disclosure that would have suggested to the skilled artisan any
advantage of filtering at 0.4 to 0.6 times the bit rate (App. Br. 7-8).
Appellants further contend that the Examiner disregarded evidence in
Appellants’ Specification showing the criticality of this range (App. Br. 8-9).
Appellant’s contentions present us with the following issues:
1. Would it have been obvious to modify Strasser to filter noise at a
3dB bandwidth between about 0.4 to 0.6 times the bit rate to optimize a
signal-to-noise ratio of the receiver module?
2. Did Appellants disclose the criticality of filtering noise at a 3dB
bandwidth between about 0.4 to 0.6 times the bit rate?

PRINCIPLES OF LAW
“[D]iscovery of an optimum value of a result effective variable in a
known process is ordinarily within the skill of the art.” In re Boesch, 617
F.2d 272, 276 (CCPA 1980) (citations omitted). However, a particular
parameter must first be recognized as a result effective variable before
optimization can be characterized as routine experimentation. In re Antonie,
559 F.2d 618, 621 (CCPA 1977).
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Application 10/427,210

4
“[W]here the general conditions of a claim are disclosed in the prior
art, it is not inventive to discover the optimum or workable ranges by routine
experimentation.” In re Aller, 220 F.2d 454, 456 (CCPA 1955).
To show criticality of the claimed range, “‘it is not inventive to
discover the optimum or workable ranges by routine experimentation.’ Only
if the ‘results of optimizing a variable’ are ‘unexpectedly good’ can a patent
be obtained for the claimed critical range. ” In re Geisler, 116 F.3d 1465,
1469 (Fed. Cir. 1997) (internal citations omitted).

ANALYSIS
Each independent claim (1, 11, 15, 16, and 26) recites filtering noise
from the electrical signal at a 3dB bandwidth between about 0.4 to 0.6 times
the bit rate.
The Examiner concludes that it would have been obvious to modify
Strasser’s receiver module to filter noise at a 3dB bandwidth between about
0.4 to 0.6 times a bit rate, because where the general conditions of a claim
are disclosed in the prior art, discovering the optimum or workable ranges
involves only routine skill in the art. Ans. 5, citing Aller, 220 F.2d at 456.
We disagree with the Examiner’s conclusion of obviousness. We
agree with Appellants that Strasser’s disclosure would not have presented
the skilled artisan with “a finite number of identified, predictable solutions”
(App. Br. 7). Specifically, we agree with Appellants that Figures 2(b) and
3(b) of Strasser fail to suggest that an RZ filter should be optimized by
choosing an electric filter bandwidth between 0.4 and 0.6 times the bit rate
(App. Br. 7-8).
Appeal 2010-000349
Application 10/427,210

5
Further, we agree with Appellants that Aller is not applicable because
the Examiner has failed to account for Appellants’ disclosure of the
criticality of the claimed range. Appellants disclose an impact curve of the
Q-factor versus electrical receiver filter 322 3 dB-bandwidth (Fig. 4, Spec.
10). “The optimum 411 of the impact curve 410 is located at a receiver filter
322 bandwidth of 0.45 to 0.5 times the bit rate” (Spec. 10:8-9).
Increasing the electrical filter bandwidth to the typical value of 0.7
times the bit rate introduces a Q factor penalty of about 12 dB. Further
increase of the filter bandwidth deteriorates the signal even further.
This occurs because a wider filter bandwidth increases the noise
power passing to the decision circuit, while the signal power is
increased by a smaller fraction. (Spec. 10:12-15).

Appellants’ disclosure and illustration at Figure 4 thus make clear the
critical nature of the range of 0.4 to 0.6 times the bit rate.
We therefore find that the Examiner erred in rejecting claims 1, 2, 4,
6, 15, 26, 27, 29, 30, 34, and 35 under § 103 as being unpatentable over
Strasser. We further find that the Examiner erred in rejecting claims 5, 7, 8,
10-14, 16-21, 31-33, and 36 under § 103 as being unpatentable over Strasser
in view of Kurchuk. We further find that the Examiner erred in rejecting
claims 9 and 28 under § 103 as being unpatentable over Strasser in view of
Rosencwaig. We will not sustain the Examiner’s rejections.

CONCLUSIONS
1. It would not have been obvious to modify Strasser to filter noise at
a 3dB bandwidth between about 0.4 to 0.6 times the bit rate to optimize a
signal-to-noise ratio of the receiver module.
Appeal 2010-000349
Application 10/427,210

6
2. Appellants disclosed the criticality of filtering noise at a 3dB
bandwidth between about 0.4 to 0.6 times the bit rate.

ORDER
The Examiner’s rejection of claims 1, 2, 4-21, and 26-36 is reversed.

REVERSED

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