Ex Parte Kerth et al

Board of Patent Appeals and Interferences

Jan 12, 2009

10452192 (B.P.A.I. Jan. 12, 2009)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte DONALD A. KERTH and G. DIWAKAR VISHAKHADATTA
____________

Appeal 2008-4813
Application 10/452,192
Technology Center 2600
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Decided: January 12, 2009
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Before KENNETH W. HAIRSTON, MAHSHID D. SAADAT,
and SCOTT R. BOALICK, Administrative Patent Judges.

SAADAT, Administrative Patent Judge.

DECISION ON APPEAL
Appellants appeal under 35 U.S.C. § 134(a) from the Examiner’s
Final Rejection of claims 1-6, 10-12, and 14-20. Claims 7-9 and 13 have
been indicated by the Examiner as containing allowable subject matter. We
have jurisdiction under 35 U.S.C. § 6(b).
We reverse.
Appeal 2008-4813
Application 10/452,192

STATEMENT OF THE CASE
Appellants’ invention relates to radio frequency (RF) receivers that
perform image rejection through conversion of RF signal to an intermediate
frequency (IF) signal. (Spec. 1-2).
Independent Claim 1 is representative and reads as follows:
1. A radio frequency (RF) receiver comprising:

an image signal synthesizer having an output for providing a
tone signal at an image frequency;

a down converter having an input for receiving an RF input
signal during a normal operation period and said tone signal during a
calibration period, and an output for providing an IF input signal at
another frequency; and

a signal processor having an input coupled to said output of said
down converter, and an output for providing a corrected signal,
including:

an image correction network having first and second
coefficients, wherein during said calibration period said signal
processor determines best values of said first and second
coefficients by measuring a wanted energy level at baseband of
said IF input signal while said first and second coefficients are
varied and choosing values for said first and second coefficients
that tend to yield a lowest value of said wanted energy, and
during said normal operation period said image correction
network filters said IF input signal at said other frequency using
said best values.

The Examiner relies on the following prior art references in rejecting
the claims:
Golan US 5,826,180 Oct. 20, 1998
Glas US 6,330,290 B1 Dec. 11, 2001

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Application 10/452,192

Claims 1-6, 10-12, and 14-20 stand rejected as being unpatentable
under 35 U.S.C. § 103(a) over Golan and Glas.
Rather than repeat the arguments here, we make reference to the
Briefs and the Answer for the respective positions of the Appellants and the
Examiner.
ISSUE
The issue is whether Appellants have shown that the Examiner erred
in rejecting the claims under 35 U.S.C. § 103. The issue on appeal turns on
whether substantial evidence before us shows that under 35 U.S.C. § 103,
the combination of Golan and Glas teaches or suggests the claimed subject
matter. Specifically, Appellants (App. Br. 7) and the Examiner (Ans. 11)
disagree as to whether Glas discloses or suggests determining best values of
said first and second coefficients by measuring a wanted energy level while
varying the first and second coefficients and choosing values for said first
and second coefficients that tend to yield a lowest value of said wanted
energy.

FINDINGS OF FACT
The following findings of fact (FF) are relevant to the issue involved
in the appeal.
Golan
1. Golan relates to a radio frequency receiver including a tuning
unit, an in-phase-quadrature (I/Q) mixer, and a calibrated image rejection
processor. (Abstract).
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Application 10/452,192

2. As depicted in Figure 3, Golan provides for a processor 24
comprising a calibration determiner 23, an I/Q corrector 25, and an image
rejector 27 (col. 3, ll. 60-65).
3. During calibration, Golan coefficients are determined for
generating the desired corrected signals. (Col. 5, ll. 3-36).
Glas
4. Glas relates to “a demodulator and more specifically to an
arrangement for compensating I/Q imbalances caused by imbalances in the
receive chain of a communication terminal” (col. 1, ll. 4-7).
5. Glas specifically provides a compensation arrangement that
overcomes the phase and amplitude imbalances caused by the local
oscillator employed in the receiver which includes a first RF mixing stage
and a second IF mixing stage (col. 2, ll. 29-35).
6. Glas teaches that during operation, a test tone signal is
generated and provided to the receiver. Both desired and image band signals
are measured and based on those measurements, the value of the
compensation factors are derived. (Col. 2, ll. 44-47).
7. As shown in Figure 2, Glas discloses a transceiver including an
RF mixing stage 30 filters IF signals via filters 25’ and 26’ and converts the
signals to digital domain via analog to digital (A-D) converters 27 and 27’
(col. 5, ll. 45-48).
8. Glas also describes compensating units 102 and 104, which are
configured to multiply the output signals of A-D converters 27 and 27’ by
factors β and α (col. 5, ll. 50-58).
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9. During calibration, test tone signal generator 128 provides the
test tone to transceiver 10 while both desired and image signals are
measured in the digital IF mixing stage (col. 6, ll. 24-31).
10. Glas sets the compensation factors to β=0 and α=1 in order to
estimate the imbalance and later changes these values to derive the proper
imbalance compensation (col. 6, ll. 39-42).
11. Glas further teaches that the imbalances defined by equations
17a and 17b are estimated for a number of frequency points and stored in
digital signal processor 56, so as to derive compensation factors for various
frequency operations (col. 7, ll. 43-47).
12. Glas further discloses that the values of α and β may be derived
from their fixed values based on equations 20a and 20b or be calculated
using equations 23a and 23b (col. 9, l. 38; col. 10, ll. 30-39).

PRINCIPLES OF LAW
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 (Fed. Cir. 1988). In so
doing, the Examiner must make the factual determinations set forth in
Graham v. John Deere Co., 383 U.S. 1, 17 (1966). “[T]he examiner bears
the initial burden, on review of the prior art or on any other ground, of
presenting a prima facie case of unpatentability.” In re Oetiker, 977 F.2d
1443, 1445 (Fed. Cir. 1992).
“[I]t can be important to identify a reason that would have prompted a
person of ordinary skill in the relevant field to combine the elements in the
way the claimed new invention does.” KSR Int'l v. Teleflex Inc., 127 S. Ct.
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1727, 1741 (2007). “[T]here must be some articulated reasoning with some
rational underpinning to support the legal conclusion of obviousness.” In re
Kahn, 441 F.3d 977, 988 (Fed. Cir. 2006) (citing In re Lee, 277 F.3d 1338,
1343-46 (Fed. Cir. 2002); In re Rouffet, 149 F.3d 1350, 1355-59 (Fed. Cir.
1998)).
Further, a rejection based on section 103 must rest upon a factual
basis rather than conjecture, or speculation. “Where the legal conclusion [of
obviousness] is not supported by the facts it cannot stand.” In re Warner,
379 F.2d 1011, 1017 (CCPA 1967). See also In re Kahn, 441 F.3d at 988
(Fed. Cir. 2006).
ANALYSIS
With respect to claim 1, the Examiner’s reading of the image signal
synthesizer, down converter, and the signal processor of the claimed radio
frequency receiver on the receiver disclosed by Golan (Ans. 3-4) appears to
remain undisputed by Appellants (App. Br. 6-7). However, Appellants
challenge the Examiner’s characterization of the way Glas derives
compensation factors α and β as the claimed varying the coefficients and
choosing them in order to yield a lowest value of the wanted energy (App.
Br. 7). Appellants point to columns 6-10 of Glas and specifically argue (id.)
that although Glas sets the compensation factors α and β to default values to
later change the factors, nowhere does the reference teach determining these
factors by measuring a wanted energy level as the factors are varied. The
Examiner responds by relying on column 2, lines 44-47 of Glas which states:
During operation, a test tone signal is generated and provided to
the receiver. Both desired and image band signals are measured and
based on those measurements the value of the compensation factors
are derived.
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The Examiner concludes that “[S]ince the original setting of the coefficients
are changed according to the measured signals in order to determine the best
values, they are interpreted as being varied in order to determine the best
value” (Ans. 11-12).
Appellants further argue (Reply Br. 2-3) that both references calculate
coefficients by direct approach while “Golan discloses an apparatus for
measuring the values of the amplitude error ε and the phase error α directly
by generating the autocorrelations of I(t) and Q(t) and the cross-correlation
between I(t) and Q(t).” Additionally, Appellants contend (Reply Br. 3) that
Glas does not determine the coefficients indirectly by varying them during a
single calibration period and instead, sets the coefficients’ values and
changes them later by direct computation.
Upon a review of the prior art teachings, we disagree with the
Examiner’s characterization of the change made to the values of the
coefficients in Glas as the claimed varying and choosing the coefficient
values that yield a lowest value of said wanted energy. Claim 1 requires
determining the coefficient values during the calibration period by varying
them until a lowest value of wanted energy is obtained. As described above,
Glas determines the coefficient values by setting them to an initial value and
later changing them to a calculated or derived value (FF 4-9) without taking
into account how the coefficient value changes the wanted energy to its
lowest value. Glas specifically sets the coefficients to their initial values and
later changes the values (FF 10).
Contrary to the Examiner’s position, Glas calculates the coefficient
based on equations for a number of frequencies and stores the calculated
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values as compensation factors for different frequency operations (FF 11).
Similarly, Glas discloses that the deriving of the coefficient values are based
on calculations using fixed values consistent with equations 20a, 20b or
using equations 23a and 23b (FF 12). As such, Glas determines the
coefficients based on straight calculations, and not based on varying the
coefficient values until they yield the lowest value of wanted energy, as
recited in claim 1.

CONCLUSION
On the record before us, we find that the Examiner failed to make a
prima facie case that the combination of Golan and Glas would have
suggested the recited features of claim 1 or other independent claims 11 and
18, which include similar limitations. Therefore, in view of our analysis
above, we do not sustain the 35 U.S.C. § 103 rejection of claims 1, 11, and
18, nor of any claims dependent thereupon, as being obvious over Golan and
Glas.

DECISION
The decision of the Examiner rejecting claims 1-6, 10-12, and 14-20
is reversed.

REVERSED

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