Ex Parte Lin et al

Patent Trial and Appeal Board

Feb 24, 2016

12490345 (P.T.A.B. Feb. 24, 2016)

UNITED STA TES p A TENT AND TRADEMARK OFFICE
APPLICATION NO. FILING DATE
12/490,345 0612412009
127226 7590 02/26/2016
Birch, Stewart, Kolasch & Birch, LLP
P.O. Box 747
Falls Church, VA 22040-0747
FIRST NAMED INVENTOR
Wei-Chun Lin
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
ATTORNEY DOCKET NO. CONFIRMATION NO.
6257-0111PUS1 3311
EXAMINER
ELBIN, JESSE A
ART UNIT PAPER NUMBER
2656
NOTIFICATION DATE DELIVERY MODE
02/26/2016 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):
mailroom@bskb.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Exparte WEI-CHUN LIN and YI-CHANG TU1
Appeal2014-002501
Application 12/490,345
Technology Center 2600
Before ALLEN R. MacDONALD, KEVIN C. TROCK, and
AMBER L. HAGY, Administrative Patent Judges.
HAGY, Administrative Patent Judge.
DECISION ON APPEAL
STATEMENT OF THE CASE
Appellants appeal under 35 U.S.C. § 134(a) from the Final Rejection
of claims 1-15 and 17-22. We have jurisdiction under 35 U.S.C. § 6(b ).
We reverse.
1 Appellants identify Realtek Semiconductor Corporation as the real party in
interest. (App. Br. 3.)
Appeal2014-002501
Application 12/490,345
Introduction
According to Appellants, "[t]he present invention relates to a digital-
to-analog converter, and more particularly, to a digital-to-analog converter
for reducing pop noise and harmonic tone and related converting method."
(Spec. ii 1.)
Exemplary Claim
Claim 1, reproduced below, is exemplary of the claimed subject
matter:
1. An apparatus for converting a digital audio signal into an
analog audio signal, the apparatus comprising:
a first circuit configured to receiving the digital audio
signal and converting the digital audio signal into an N-bit
sigma-delta modulation signal, wherein N is larger than 1;
a multiplexer, for receiving the N-bit sigma-delta
modulation signal and a zero signal, and selectively outputting
the N-bit sigma-delta modulation signal or the zero signal as an
output signal according to a selection signal;
a low-pass filter, coupled to the multiplexer, for
generating a filtered output signal according to the output
signal, wherein the filtered output signal is a pulse-code
modulation (PCM) signal; and
a digital-to-analog converter, coupled to the low-pass
filter, for generating the analog audio signal according to the
filtered output signal.
REFERENCES
The prior art relied upon by the Examiner in rejecting the claims on
appeal is:
Matsumoto
Miller
US 6,927,720 B2 Aug. 9, 2005
US 2005/0063476 Al Mar. 24, 2005
2
Appeal2014-002501
Application 12/490,345
REJECTION
Claims 1-15 and 17-22 stand rejected under 35 U.S.C § 103(a) as
being unpatentable over Matsumoto and Miller. (Final Act. 2-17.)
ANALYSIS
The Examiner cites Matsumoto as teaching the limitations of claim 1
except for the multiplexer limitation, for which the Examiner relies on
Miller. (Final Act. 3.) As to the basis for combining these references, the
Examiner states: "It would have been obvious to one of ordinary skill in the
art at the time of the invention to include a multiplexer as taught by Miller
prior to the digital-to-analog conversion taught by Matsumoto for the benefit
of muting the audio signal when no valid audio data is present." (Final Act.
4.)
Appellants argue the Examiner's findings are in error because the
cited references, alone or in combination, do not teach or suggest a
generating a pulse-code modulation (PCM) filtered output signal according
to the output signal of the multiplexer, as recited in claim 1. (App. Br. 12-
17; Reply Br. 24--26.) In particular, Appellants note Miller (in Fig. 7b)
teaches a PCM audio signal as an input to the circuit, but not as an output
from the multiplexer. (App. Br. 13-14.) We agree with Appellants. The
PCM signal shown in Miller's Fig. 7b is shown as an input to a compare
circuit (720), which is then used to generate a mute signal (725); the PCM
signal is also shown as an input to an asynchronous rate converter, when is
then input to a modulator (209) that outputs a pulse-width modulated signal
to the multiplexer (726). (Miller Fig. 7b and i-fi-1 7 4--77.) As Appellants
correctly note, Miller does not disclose filtering the output of the multiplexer
3
Appeal2014-002501
Application 12/490,345
to generate a PCM signal, nor does the Examiner make any findings to that
effect.
Appellants further point out the output of the low pass filter of
Matsumoto is not a "pulse-code modulation (PCM) signal," as recited in
claim 1. (App. Br. 15.) We agree with Appellants. Matsumoto discloses
the output of the delta-sigma modulator is a pulse density modulated (PDM)
signal. (App. Br. 15 (citing Matsumoto col. 111. 29-34).) The Examiner
finds, however, "the output of the circuit illustrated in Figure 2 [of
Matsumoto] can reasonably be considered a pulse-code modulation (PCM)
signal." (Advisory Action dated May 3, 2013 (hereafter "Adv. Act.") 2.)
The Examiner further finds:
[O]ne ordinarily skilled in the art would recognize that the
various well-known digital modulation scheme names do not
precisely define the specifics of the modulation scheme, and
that significant overlap exists between the various modulation
schemes and the names of said modulation schemes.
ii:\.ccordingly, [the] Examiner maintains that it is reasonable to
equate the claimed ''pulse-code modulation" with the explicitly
taught ''pulse density modulated" signal of Matsumoto.
(Ans. 15-16 (emphasis added).)
We are persuaded by Appellants' arguments, however, that the
Examiner has not supported the finding equating the "pulse-density
modulation" output signal of Matsumoto with the claimed "pulse-code
modulation" filtered output signal. (Reply Br. 28-29.) The Examiner cites
to an IEEE dictionary that defines "pulse-code modulation," but, as the
Examiner concedes, that dictionary does not mention "pulse-density
modulation." (Ans. 15-16.) We agree with Appellants that the silence of
that dictionary on a definition for "pulse-density modulation" does not
support equating these types of modulation. Moreover, as Appellants point
4
Appeal2014-002501
Application 12/490,345
out, PCM samples the magnitude of the analog signal, whereas, in PDM,
specific magnitudes are not encoded but it is the relative density of the
pulses that corresponds to the analog signal's magnitude. (Reply Br. 28-
29.) The Examiner has not explained why these differences may be
disregarded in the context of the claimed invention.
Still further, in addition to the defects in the Examiner's findings
regarding the individual references, we are persuaded the Examiner has
failed to present a prima face case of obviousness with regard to combining
the references. The Examiner bears the initial burden of factually supporting
any prima facie conclusion of obviousness. The key to supporting any prima
facie conclusion of obviousness is the clear articulation of a reason why the
claimed invention would have been obvious. The Supreme Court in KSR
Int'! Co. v. Teleflex Inc., 550 U.S. 398, 418 (2007), held that the analysis
supporting a rejection under 35 U.S.C. § 103 should be made explicit. The
Court also stated that "rejections on obviousness grounds cannot be
sustained by mere conclusory statements; instead, there must be some
articulated reasoning with some rational underpinning to support the legal
conclusion of obviousness." KSR, 550 U.S. at 418 (quoting In re Kahn, 441
F.3d 977, 988 (Fed. Cir. 2006)).
In the present case, the Examiner has not provided articulated
reasoning for combining the multiplexer taught by Miller with the digital-to-
analog conversion taught by Matsumoto. At most, the Examiner asserts it
would have been obvious "to include a multiplexer as taught by Miller prior
to the digital-to-analog conversion taught by Matsumoto for the benefit of
muting the audio signal when no valid audio data is present." (Ans. 14.)
This statement is conclusory and lacks articulated reasoning. Moreover,
5
Appeal2014-002501
Application 12/490,345
Appellants have persuasively set forth reasons why one of ordinary skill in
the art would not be motivated to combine the teachings of the cited
references-in particular, because they apply different modulation schemes.
(App. Br. 16; Reply Br. 29-31.) Although the Examiner finds "one
ordinarily skilled in the art would recognize any differences in the operation
of the digital circuit and could readily make the requisite changes" (Ans.
16), the Examiner does not provide a factual basis for this finding.
In short, we are persuaded by Appellants that the Examiner did not
present a prima facie case of unpatentability in the rejection of independent
claim 1 under§ 103(a) over Matsumoto and Miller. We, therefore, do not
sustain the Examiner's rejection of claim 1, as well as independent claim 17,
which recites limitations commensurate with the above-referenced
limitations of claim 1. We also do not sustain the Examiner's rejection of
dependent claims 2-15 and 18-22, which stand with their respective
independent claims.
DECISION
For the above reasons, the Examiner's 35 U.S.C. § 103(a) rejection of
claims 1-15 and 1 7-22 is reversed.
REVERSED
6