Ex Parte Foote

Patent Trial and Appeal Board

Feb 21, 2018

13849761 (P.T.A.B. Feb. 21, 2018)

United States Patent and Trademark Office
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O.Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
13/849,761 03/25/2013 Garritt W. Foote 6150-52400 1011
35690 7590 02/23/2018
MEYERTONS, HOOD, KIVLIN, KOWERT & GOETZEL, P.C.
P.O. BOX 398
AUSTIN, TX 78767-0398
EXAMINER
YENINAS, STEVEN LEE
ART UNIT PAPER NUMBER
2868
NOTIFICATION DATE DELIVERY MODE
02/23/2018 ELECTRONIC
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
patent_docketing@intprop.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte GARRITT W. FOOTE
Appeal 2017-006225
Application 13/849,761
Technology Center 2800
Before ROMULO H. DELMENDO, KAREN M. HASTINGS, and
JAMES C. HOUSEL, Administrative Patent Judges.
PER CURIAM.
DECISION ON APPEAL
The Appellant1 appeals under 35 U.S.C. § 134(a) from the Primary
Examiner’s final decision to reject claims 1-27.2 We have jurisdiction under
35 U.S.C. § 6(b).
We affirm.
1 The Appellant is the Applicant, National Instruments Corporation, which,
according to the Brief, is the real party in interest. Appeal Brief filed on
June 29, 2016, hereinafter “Appeal Br.,” 2.
2 Appeal Br. 4-22; Final Office Action (notice emailed on January 6, 2016)
hereinafter “Final Act.,” 2-23; Examiner’s Answer (notice emailed on
January 3, 2017), hereinafter “Ans.,” 2-24; Reply Brief filed on March 3,
2017, hereinafter “Reply Br.,” 2-10.
Appeal 2017-006225
Application 13/849,761
I. BACKGROUND
The inventor states that the accuracy of electronic components used in
common measurement devices, such as current transformers in current­
monitoring circuits, can vary. Specification filed on March 25, 2013,
hereinafter “Spec.,” ^ 5. This, according to the inventor, is a result of power
transfers via the magnetic flux of the transformer core not being 100%
efficient and error free. Id. The inventor states that modem power
measurement devices have various options to address this issue, but these
options include physically large current transformers or multiple current
transformers. Id. In view of this, the inventor discloses a measurement
circuit having many of the benefits of closed-loop magnetic sensor designs
but not the increased size and cost due to an extra winding and magnetic
sensor. Id. ^ 44.
Representative claim 1 is reproduced from page 2 of the Response to
Notification of Non-Compliant Appeal Brief filed September 12, 2016, as
follows (emphases added):
1. A feedback circuit comprising:
a first terminal configured to couple to a first end of two
ends of a conductor winding; and
a second terminal configured to couple to a second end of
the two ends of the conductor winding;
wherein the feedback circuit is configured to:
reduce an error current to at least a specified level
in the conductor winding at AC frequencies by driving a
secondary current in the conductor winding; and
eliminate a DC current flux from the feedback
circuit at low frequencies.
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Application 13/849,761
II. REJECTIONS ON APPEAL
On appeal, the Examiner maintains two rejections under post-AIA
35 U.S.C. § 103, as follows (Ans. 2; Final Act. 6-23):
A. Claims 1-7, 9-16, 19-25, and 27 as being unpatentable
over Edel3 in view of Mende;4 and
B. Claims 8, 17, and 26 as being unpatentable over Edel in
view of Mende and further in view of Gibellini.5
III. DISCUSSION
Rejection A
Claims 1-7, 9-16, 19-25, and 27 are rejected under 35 U.S.C. § 103
as being unpatentable over Edel in view of Mende. The Appellant provides
arguments under multiple sub-headings identified by various claim(s).
Appeal Br. 4-21. We address claims separately from representative claim 1
only to the extent that they have been argued separately pursuant to
37C.F.R. §41.37(c)(l)(iv).
Claim 1
The Examiner finds Edel discloses a feedback circuit that includes a
first terminal (the terminal located near the “+” sign for voltage V2 in Figure
3, which is labeled as “PRIOR ART”) and a second terminal (the terminal
located near the sign for voltage V2 in Figure 3), wherein the feedback
circuit is configured to reduce an error current to at least a specified level at
AC frequencies by driving a secondary current in a conductor winding, as
3 US 6,954,060 Bl, issued on Oct. 11, 2005.
4 US 6,836,107 B2, issued on Dec. 28, 2004.
5 US 7,525,297 B2, issued on Apr. 28, 2009.
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Application 13/849,761
required by claim 1. Final Act. 6-7. The Examiner finds Edel’s Figure 3
disclosure differs from claim 1 ’s subject matter in that it does not disclose
that the feedback circuit is configured to eliminate a DC current flux from
the feedback circuit at low frequencies, as recited in claim 1. Id. at 7.
The Examiner finds Mende discloses a device that eliminates DC
current flux from a feedback circuit at low frequencies. Id. The Examiner
concludes it would have been obvious to one of ordinary skill in the art to
have modified Edel’s feedback circuit in view of Mende to improve current
transformer accuracy, as an application of “conventional DC blocking
methods well established in the art.” Id. at 7-8.
The Appellant contends: Mende does not teach or suggest a device
functioning to “eliminate a DC current flux from the feedback circuit at low
frequencies,” as recited in claim 1; the Examiner misinterprets individual
features in the systems of Edel and Mende; the Examiner relies upon
knowledge gleaned only from the inventor’s disclosure; and, in view of
these arguments, there would have been a lack of reason to modify Edel in
view of Mende. Appeal Br. 5-8; Reply Br. 2^1. Specifically, the Appellant
asserts that Edel and Edel ’5176 warn again the complete cancellation of the
loop impedance (i.e., the elimination of the current flux) and that Edel and
Mende address different deficiencies and relate to different techniques, so
one of ordinary skill in the art would have lacked a reason to modify Edel in
view of Mende. Appeal Br. 8-13; Reply Br. 4-9.
6 Edel, US 6,522,517 Bl, issued Feb. 18, 2003 (“Edel ’517”). Edel cites and
incorporates by reference Edel ’517 in its discussion of the embodiment
depicted in Figure 3. Edel 5:12-17.
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Appeal 2017-006225
Application 13/849,761
The Appellant’s arguments are unpersuasive. Consistent with the
Examiner’s findings, we find Edel discloses a circuit that includes a
transformer CT1, a current-sensing resistor Rl, and a controllable voltage
device 5B. Edel 9:59-10:2. The controllable voltage device 5B is
connected to the secondary winding of the transformer CT1 via the terminals
identified by the Examiner. Id. at Fig. 3. Edel discloses that the circuit
generates a compensation voltage to drive secondary current so that flux
changes in the current transformation core are reduced. Id. at 5:18-26,
7:26-35.
Mende discloses a coupling circuit 60 connected to a current probe 12
(i.e., a transformer). Mende 3:46-52, Fig. 2. The coupling circuit 60
includes, among other things, a shunt capacitor and a termination resistor 70.
Id. at 3:58-63, Fig. 2. Mende discloses that the capacitor is part of a
resistive-capacitive network that has a low frequency cutoff (e.g., less than
10 hertz) and is coupled to a resistive-inductive network “for terminating DC
and low frequency signal components of the current output signal below the
low frequency cutoff of the resistive-capacitive network.” Id. at 3:3-11.
Thus, Mende discloses a structure for eliminating a DC signal component.
Further, Edel recognizes problems due to a DC signal component by
disclosing it “causes the magnetic core to experience a large magnetomotive
force, which can cause the core to saturate, and thereby cause severe
distortion of the secondary current” and that this results in error. Edel 3:23-
28, 4:13-21. Mende also recognizes this problem by disclosing that its
circuit acts “to prevent transformer saturation of the current measurement
probe” (i.e., the transformer). Mende 3:11-14. Therefore, the disclosures of
Edel and Mende support the Examiner’s conclusion it would have been
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obvious to modify the circuit depicted in Edel’s Figure 3 in view of Mende
to terminate a DC current component and improve the accuracy of Edel’s
circuit. See Final Act. 7-8; Ans. 8, 20-22.
The Appellant’s arguments regarding the differences between Edel
and Mende, such as differences in the problems they address and differences
in how their circuits function, do not identify a reversible error in the
Examiner’s rejection. As noted above, Mende discloses a structure for
terminating a DC signal component and, thus, provides a means to address
the problem recognized by Edel. To the extent the Appellant’s arguments
note differences between Edel and Mende, the arguments do not explain
why the structure disclosed by Mende would not function in the circuit of
Edel and act to terminate a DC signal component, as taught by Mende.
For instance, the Appellant argues Mende’s AC-coupling circuit does
not function to eliminate a DC current flux from a feedback circuit at low
frequencies “but to filter out a DC component of a measured current when
measuring relatively small AC signal.” Appeal Br. 11-12. The Appellant
further asserts that “[ejliminating the DC component of a measured signal is
not the same as eliminating a DC current flux from a feedback circuit at low
frequencies” and that Mende’s circuit uses a constant impedance, not an
impedance that varies over frequency. Reply Br. 9 (emphasis omitted).
These arguments do not sufficiently explain why the structure
disclosed by Mende would not function to eliminate a DC current flux in
Edel, as recited in claim 1. For instance, the Appellant does not explain why
the Mende’s structure filters or eliminates a DC component but would not
eliminate a DC current flux. As noted above, Edel and Mende recognize
problems caused by the DC component of a signal. Mende discloses a
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Application 13/849,761
structure for terminating the DC component of a signal that includes a
capacitor and a resistor 70, and this structure would reasonably be expected
to terminate a DC signal component if implemented in Edel. Mende 3:3-11,
3:58-63, Fig. 2. Further, the Appellant’s arguments focusing on Figure 18
regarding the different direction Edel discloses for addressing its stability
problem (Appeal Br. 9-10) do not demonstrate a lack of reason to combine.
This is because Edel’s Figure 3 depicts a functional, useful current
transformer circuit—albeit in the context of Edel’s discussion of prior art.
Something that is known or obvious does not become patentable simply
because it has been described as somewhat inferior to some other product for
the same use. In re Gurley, 27 F.3d 551, 553 (Fed. Cir. 1994).
To the extent Mende does not explicitly disclose that its structure
eliminates a DC current flux, as recited in claim 1, the Examiner articulated
a sufficient reason (i.e., to eliminate a DC signal component and, thus,
improve current transformer accuracy) for combining Edel and Mende in the
manner claimed by the inventor. The fact that the inventor discovered an
additional or related advantage (elimination of DC current flux) does not
necessarily confer patentability absent a showing that the advantages
actually obtained would have been considered unexpected by a person
skilled in the relevant art. Ex parte Obiaya, 227 USPQ 58, 60 (BPAI 1985)
(“The fact that appellant has recognized another advantage which would
flow naturally from following the suggestion of the prior art cannot be the
basis for patentability when the differences would otherwise be obvious.”);
In reKubin, 561 F.3d 1351, 1357 (Fed. Cir. 2009) (“Even if no prior art of
record explicitly discusses the [limitation], [applicant’s] application itself
instructs that [the limitation] is not an additional requirement imposed by the
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claims on the [claimed invention], but rather a property necessarily present
in [the claimed invention].”).
The Appellant argues Edel and Edel ’517 warn against the “complete
cancellation of the loop impedance, i.e. the elimination of the current flux.”
Appeal Br. 9 (emphasis added). However, as stated by the Appellant {id.),
Edel ’517 states “[c]are must be exercised, however, because if the gain is
set to compensate for more than the total secondary circuit impedance, then
the system becomes unstable and current will increase to the limit of the
amplifier output circuit.” Edel ’517, 38:1-5 (emphasis added). Thus, Edel
’517 cautions against compensating for more than the secondary circuit
impedance, not against complete cancellation of the loop impedance, as
argued by the Appellant.
For these reasons and those set forth in the Examiner’s Answer, the
Appellant’s arguments do not identify a reversible error in the Examiner’s
rejection of claim 1. The Appellant does not provide any argument in
support of the separate patentability of claims 2, 3, 5-7, 9-12, 14-16, 19-21,
23-25, and 27 pursuant to the requirements set forth in 37 C.F.R.
§ 41.37(c)(l)(iv). Appeal Br. 14-16, 18. Therefore, we sustain the rejection
of these claims for the same reasons discussed for claim 1.
Claims 4, 13, and 22
Claims 4, 13, and 22 respectively depend from claims 1,10, and 19.
Due to the similarity of the arguments presented for these claims, we address
the arguments together for purposes of efficiency.
The Appellant asserts the amplifiers of Edel and Mende differ and
provide different functions and, therefore, it would not have been obvious to
modify Edel in view of Mende. Id. at 17-21. These arguments are
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Application 13/849,761
unpersuasive. The Appellant’s Specification, paragraph 47, states a
capacitance and resistance function to eliminate DC flux and to force DC
current to zero. As discussed above, Edel and Mende provide a sufficient
reason to arrive at a circuit encompassed by claim 1. To any extent Mende
does not explicitly disclose that its structure does not force a DC current to
zero, as recited in claims 4, 13, and 22, the result recited in these claims
would naturally follow from the prior art’s motivation to combine.
For these reasons and those discussed in the Examiner’s Answer, we
uphold the Examiner’s § 103 rejection of claims 1-7, 9-16, 19-25, and 27
over Edel in view of Mende.
Rejection B
Claims 8, 17, and 26 are rejected under 35 U.S.C. § 103 as being
unpatentable over Edel in view of Mende and further in view of Gibellini.
The Appellant does not present any arguments in support of the
separate patentability of claims 8, 17, and 26. Rather, the Appellant merely
reiterates the arguments set forth in support of the patentability of claims 1,
10, and 19. Appeal Br. 21-22. For the reasons set forth above, those
arguments do not identify a reversible error.
For these reasons and those discussed in the Examiner’s Answer, we
uphold the Examiner’s § 103 rejection of claims 8, 17, and 26 over Edel,
Mende, and Gibellini.
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IV. SUMMARY
The Examiner’s decision to reject claims 1-27 is affirmed.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a).
AFFIRMED
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