Ex Parte LI

Board of Patent Appeals and Interferences

Apr 23, 2009

11055127 (B.P.A.I. Apr. 23, 2009)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte QIANG LI
____________

Appeal 2009-1378
Application 11/055,127
Technology Center 2800
____________

Decided:1 April 23, 2009
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Before JOSEPH F. RUGGIERO, CARLA M. KRIVAK,
and KARL D. EASTHOM, Administrative Patent Judges.

EASTHOM, Administrative Patent Judge.

DECISION ON APPEAL

1 The two-month time period for filing an appeal or commencing a civil
action, as recited in 37 C.F.R. § 1.304, begins to run from the decided date
shown on this page of the decision. The time period does not run from the
Mail Date (paper delivery) or Notification Date (electronic delivery).
Appeal 2009-1378
Application 11/055,127

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STATEMENT OF THE CASE
Appellant appeals under 35 U.S.C. § 134 from the Final Rejection of
claims 1-20, the only claims pending (App. Br. 1).2 We have jurisdiction
under 35 U.S.C. § 6(b).
We affirm.
According to Appellant, the invention relates to compensating the Q
factor of a voltage controlled oscillator (VCO) buffer at a low frequency
band. Prior art VCOs and the VCO buffers typically employ LC tuning to
cover a wide frequency range, increasing the capacitance as the frequency
decreases. However, the increased capacitance typically lowers the output
swing. To compensate for the swing over a wide frequency range, the
invention employs a current stirring unit and variable capacitance that each
depend on a frequency of an input signal. (Spec. 1:12-30; 2: 23-30; 4: 2-18).
Claim 1, illustrative of the invention, follows:
1. A voltage controlled oscillator (VCO) buffer for a local
oscillator (LO) generator system, the VCO buffer comprising:
a VCO buffer core configured to receive an input signal having a
frequency and further configured to generate an output signal based on the
input signal;
a capacitor bank coupled to the VCO buffer core, wherein the
capacitor bank is configured to provide a variable capacitance; and
a current stirring unit coupled to the VCO buffer core, the current
stirring unit being configured to provide a current to the VCO buffer core,

2 Appellant’s Brief (filed Jan. 22, 2008) (“App. Br.”) and Reply Brief (filed
May 27, 2008) (“Reply Br.”), and the Examiner’s Answer (mailed Mar. 24,
2008) (“Ans.”), detail the respective positions of the parties.
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Application 11/055,127

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wherein the capacitance of the capacitor bank and a magnitude of the
current provided by the current stirring unit vary based on the frequency of
the input signal.
The Examiner relies on the following prior art reference:
Clarke US 6,337,604 B1 Jan. 8, 2002

The Examiner rejected:
Claims 1-7 and 9-20 as anticipated under 35 U.S.C. § 102(b) based on
Clarke.
Claim 8 as obvious under 35 U.S.C. § 103(a) based on Clarke.
ISSUE
Appellant’s arguments (Reply Br. 2) focus on the input signal and the
type of buffer recited in claim 1. Hence, the issue on appeal is: Did
Appellant demonstrate that the Examiner erred in finding that Clarke
discloses a VCO buffer, and a capacitance and current varying as a function
of input frequency, as set forth in representative claim 1?3

3 Appellant presents similar arguments for independent claims 1, 10 and 17,
primarily relying on arguments presented for claim 1 (see App. Br. 5-8,
Reply Br. 2, 3). Appellant’s recitation (App. Br. 7, 8) of claim elements for
claims 10 and 17 and reliance on arguments presented for claim 1 do not
constitute separate arguments for patentability. Accordingly, pursuant to 37
C.F.R. § 41.37(c) (1) (vii), claim 1 is selected to represent the claims
rejected as anticipated by Clarke.
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FINDING OF FACT (FF)
1. Appellant states: “In an exemplary embodiment according to the
present invention, a VCO buffer for an LO generator system is provided”
(Spec. 2:6-7). “In another exemplary embodiment according to the present
invention, an LO generator system includes a VCO, a VCO buffer and at
least one divider” (Spec. 2:17-19). “The VCO 104 receives a control signal
(or a control voltage) 102, which is used to adjust the frequency of its
output” (Spec 4:27-29).
2. Clarke discloses an adjustable crystal oscillator having a variable
output frequency and constant output swing, and states that “the centre [sic]
frequency produced by a crystal oscillator may be adjusted by changing or
trimming the load capacitance of the crystal.” (Clarke, col. 1, ll. 9-17).
Clarke’s invention changes the oscillator “centre frequency” and the output
frequency of the oscillator circuit by altering the capacitance (col. 1, ll. 43-
47).
3. Clarke’s crystal oscillator 1 is connected to a crystal oscillator
circuit 3. The circuit 3 comprises adjustable load capacitors C1 to C6 and
resistors R1 to R4. The total capacitance and resistance are adjusted
depending on the output frequency as measured by frequency measurement
device 7. Varying the capacitance varies the desired output frequency.
Varying the resistance varies the oscillator core current which controls
output swing. (Clarke, Fig. 1; Abstract; col. 2, ll. 3-48).
4. A set of transistors Q4 and Q5 between the capacitor bank and
output generate a clock output frequency 5 based, inter alia, on an input
from the crystal oscillator 1, and prevent loading of the crystal oscillator
(id.).
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5. Based on the measured output frequency at frequency
measurement device 7, a 6 bit trim register circuit 21 receives a signal from
CLK OUT 5 via the device 7 and processor 23, and outputs control bits D0-
D5. The control bits control switches to individual capacitors C1 to C6 in
the capacitor bank and resistors R1 to R4 in the resistor bank, setting a total
value of the resistance and capacitance as seen by the crystal oscillator.
Based on the control bits, selectable transistors T1-T4 vary the total
resistance, and thus, the core current of the crystal which is input to the
transistor Q2, thereby compensating for the oscillator signal swing. The
varying capacitance controls the crystal oscillator 1 frequency and the
consequent circuit 3 output frequency. (Id.; col. 2, l. 49 to col. 3, l. 18).

PRINCIPLES OF LAW
“[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). Anticipation is
established when a single prior art reference discloses expressly or under the
principles of inherency each and every limitation of the claimed invention.
Atlas Powder Co. v. IRECO, Inc., 190 F.3d 1342, 1347 (Fed. Cir. 1999); In
re Paulsen, 30 F.3d 1475, 1478-79 (Fed. Cir. 1994).
ANALYSIS
Appellant’s argument (App. Br. 6) with respect to claims 1, 10, and 17
that Clarke’s crystal oscillator buffer circuit “incorrectly equates” to the
recited VCO buffer is not persuasive. Appellant’s argument fails to
demonstrate why Clarke’s buffer does not constitute the VCO buffer recited
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in claim 1. To the extent that Appellant’s argument implies that Claim 1
requires a specific type of oscillator; i.e., a VCO (voltage controlled
oscillator), the argument fails. Claim 1 does not recite a VCO, but rather,
recites a generic LO (local oscillator). Nor do the VCO buffer and VCO
buffer core recited in claim 1 implicitly require a VCO.
The VCO buffer and VCO buffer core recited indicate, at most, a
mere intended use of the exemplary type of local oscillator (i.e., a VCO type
of LO) with which the VCO buffer core may be employed. This
interpretation is consistent with Appellant’s disclosure (see FF 1). Further,
as demonstrated below, Clarke’s buffer core 3 is voltage controlled, thereby
constituting the VCO buffer core recited in claim 1.
While claim 10 recites “a voltage controlled oscillator (VCO)
configured to receive a control signal and generate an oscillation signal
having a frequency that depends on the control signal,” Appellant
emphasizes the input signal limitations of claim 1 discussed infra without
explaining why Clarke’s crystal oscillator does not constitute a VCO (App.
Br. 7, see n.3 supra). That is, as also noted supra, Appellant specifically
relies on arguments presented for claim 1 (id.).
In light of the arguments presented, the Examiner’s finding (Ans. 6)
that “a VCO is necessarily present when a VCO buffer is used in an LO
generator system” appears reasonable. Appellant does not argue that
Clarke’s crystal oscillator is not “configure[d] to receive a control signal and
generate an oscillation signal having a frequency that depends on the control
signal” as recited in claim 10 (and therefore waives this argument). In any
case, Clark’s crystal oscillator “centre” [sic] frequency signal varies as a
result of a voltage or control signal applied to the capacitor load bank (FF 2,
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5), thereby reasonably constituting a VCO since a voltage or signal controls
the crystal oscillator frequency.
Accordingly, Appellant has not rebutted the Examiner’s findings with
respect to the VCO buffer in claims 1 and 17, or the VCO and VCO buffer
in claim 10. “The problem in this case is that the appellants failed to make
their intended meaning explicitly clear.” In re Morris, 127 F.3d 1048, 1056
(Fed. Cir. 1997). “It is the applicants’ burden to precisely define the
invention, not the PTO’s.” Id.
Appellant’s argument (App. Br. 6) that Clarke’s capacitance and
current do not vary based on an “input signal” also is not persuasive.
Clarke’s input signal to the buffer core 3 from the local oscillator 1 is input
to and varied by the capacitor bank (FF 2, 5) in the buffer core 3. The signal
input from the local oscillator is also input to the transistor stage Q4/Q5
(also in the buffer core 3) to produce an output signal 5. The output
frequency is also controlled by varying the capacitance (FF 2-5). The output
signal frequency at transistors Q4/Q5 reasonably results from, or tracks, the
input frequency from oscillator 1 at base Q5 of the transistor pair Q4/Q5 (FF
2-5). In other words, the input and output frequencies vary together as a
function of the controllable capacitance and reasonably appear to be the
same controllable frequency (i.e., both equal the local oscillator frequency
input to the buffer core 3). (FF 2-5).
As the Examiner found (Ans. 3), the output frequency is measured by
frequency measurement device 7 which sends a control signal to adjust the
capacitance and the resistance banks based on the measured frequency. The
resistance banks accordingly adjust the current of the current stirring unit
(Q2, Rmin, R1-R4, T1-T4) identified by the Examiner (id.). (See FF 2-5;
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Clarke, Fig. 1). Therefore, since the output frequency tracks (or equals) the
input frequency, it follows that “the capacitance of the capacitor bank and a
magnitude of the current provided by the current stirring unit vary based on
the frequency of the input signal” as set forth in claim 1.
For the reasons discussed above, Appellant has failed to demonstrate
the Examiner erred in finding that Clarke discloses the disputed limitations
of claim 1. Therefore, we will sustain the rejection of claims 1, 10 and 17,
and dependent claims 2-7 and 9-20, not argued separately. With respect to
the rejection of claim 8, Appellant (App. Br. 8) similarly relies on arguments
made with respect to claim 1. Therefore, for reasons outlined above, we will
also sustain the rejection of claim 8.

CONCLUSION
Appellant did not demonstrate that the Examiner erred in finding that
Clarke discloses a VCO buffer, and a capacitance and current varying as a
function of input frequency, as set forth in representative claim 1.
DECISION
We affirm the Examiner's decision rejecting claims 1-20.

Appeal 2009-1378
Application 11/055,127

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No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a)(1)(iv).

AFFIRMED

KIS

BRAKE, HUGHES, BELLERMANN, L.L.P.
c/o CPA Global
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Minneapolis, MN 55402