Ex Parte Unno

Board of Patent Appeals and Interferences

Jan 22, 2009

10054604 (B.P.A.I. Jan. 22, 2009)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte TAKAHIRO UNNO

Appeal 2008-3421
Application 10/054,604
Technology Center 2600
____________

Decided: January 22, 2009
____________

Before JOHN A. JEFFERY, KARL D. EASTHOM, and R. EUGENE
VARNDELL, JR., Administrative Patent Judges.

EASTHOM, Administrative Patent Judge.

DECISION ON APPEAL
Appeal 2008-3421
Application 10/054,604

STATEMENT OF THE CASE
Appellant appeals under 35 U.S.C. § 134 from the Examiner’s
rejection of claims 3-5. Claims 1 and 2 have been allowed. No other claims
are pending. (Br. 2; Ans. 2).1 We have jurisdiction under 35 U.S.C. § 6(b).
We affirm.
Appellant describes the claimed invention as providing a layered
“CELP (code-excited linear prediction) coding with one or more filterings:
progressively weaker perceptual filtering in the encoder, progressively
weaker short-term post filtering in the decoder, and pitch postfiltering for all
layers in the decoder.” (Spec. 2: 24-25; 3: 28-31).
Claims 3-5 follow:
3. A layered encoder, comprising:
(a) an estimator for each layer of a layered encoder; and
(b) perceptual filters including inverse filters for each layer, wherein at
least one of said layer perceptual filters is weaker than another of said layer
perceptual filters.

4. A method of decoding a layered encoded signal, comprising:
(a) applying a short-term postfiltering to a synthesized layered encoded
signal wherein the short-term postfiltering differs for at least two of the
number of layers decoded to form said synthesized layered encoded signal.

5. A method of decoding a layered encoded signal, comprising:
(a) applying a long-term postfiltering to a synthesized layered encoded
signal wherein the long-term postfiltering is independent of the number of
layers decoded to form said synthesized layered encoded signal.

1 The Examiner’s Answer (electronic notification October 23, 2007)
(“Ans.”) and Appellant’s Brief (filed August 9, 2007) (“Br.”) detail the
parties’ positions.
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The Examiner relies on the following prior art reference to show
unpatentability:
Gao US 6,961,698 B1 Nov. 1, 20052

The Examiner rejected claims 3 through 5 under 35 U.S.C. § 103(a) as
being obvious based on Appellant’s admitted prior art (“APA”) and Gao.
ISSUE
With respect to claims 3-5, Appellant contends that Gao and the APA
“conflict.” Appellant also contends that the weak filter teachings of Gao do
not relate to perceptual filters with respect to claim 3, and do not relate to
encoding with respect to claim 4. (Br. 4).
The issue: Did Appellant demonstrate that the Examiner erred in
finding that Gao’s teachings apply to the APA decoding/encoding systems,
thereby meeting the weak filter element of claim 3, the different filter
element of claim 4, and the post-filtering of claim 5?
FINDINGS OF FACT (FF)
1. Appellant admits that layered CELP coding systems are known,
including encoders and decoders. Known layered CELP encoders and
decoders respectively employ the same PWF (perceptual weighting filter)
and LPC synthesis filter for each layer. (Spec. 3:7-21; 6:13-17; “Prior Art”
Figs. 2a, 2b).
2. Appellant describes “[p]erceptually filter[ing] the speech s(n) with
the perceptual weighting filter (PWF) defined by W(z) = A(z/γ1)/A(z/γ2) to

2 This reference is a divisional application of application 09/662,828, filed
September 15, 2000, now U.S. Patent No. 6,581,032.
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yield s’(n).” (Spec. 6: 5-6). Appellant states that a short term post filter
processes synthesized speech, “sharpens formants,” and has “the same form
as the perceptual weighting filter but does the opposite.” (Spec. 11: item
(7)).
3. Appellant’s system applies different filters to different code rates.
(Spec. 8: item (7); Spec. 11: item (7)).
4. Gao discloses an encoding system 12 and decoding system 16
forming a speech compression system 10. The speech compression system
encodes a speech signal 18 and then decodes it. (Fig. 1, col. 6, ll. 22-28).
Gao’s “embodiments may use the CELP coding technique as a framework . .
. .” (col. 4, ll. 36-40).
5. Gao’s system first processes speech 18 in a pre-processing unit 34,
then in a frame processing unit 44, and then further in processing modules
56-62. (Fig. 2).
6. In modules 56 and 58, a synthesis filter 462 immediately precedes
a perceptual filter 466 in a cascaded feedback manner (Fig. 11) in second
subframe processing modules 74 and 84 (compare Fig. 2 with Fig. 11) of an
encoder 12 (Fig. 2). Signals processed in a similar synthesis filter 460 are
processed in perceptual filter 464 “to provide a first resynthesized speech
signal 500.” (Gao, col. 52, ll. 63-66, Fig. 11). Multiplying the impulse
response (in the frequency domain) of each of two cascaded filters, or
convolving the responses (see col. 48, l. 65 to col. 49, l. 4), yields the system
impulse response for the two filters.
7. Gao discloses introducing a weak short-term spectral filter into the
impulse response of the second synthesis filter 462, but only for the half-rate
codec 24 (col. 53, l. 59 to col. 54, l. 6). Thus, the filters for the half-rate
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processing system 84 are different than the filters for the full-rate processing
system 74.
8. Gao teaches that decoding and encoding processes are similar.
(Col. 58, ll. 41-43).
9. Gao’s filter 98 and post processing module 100 apply to each
decoder 90, 92, 94 and 96 (col. 12, ll. 33-41; col. 58, l. 64 to col. 59, l. 4).
10. Gao’s system uses different coding techniques and assigns
different bit rates (full, half, quarter, eighth) to speech signals of different
characteristics. Within a specific full and half-rate encoder, the speech is
further encoded and classified differently based upon speech characteristics
such as rapidly changing harmonic structure (Type One) or noise-like
structure (Type Zero). (See generally col. 4, ll. 51 – col. 5, l. 26, col. 9, l. 46
– col. 12, l. 7; Fig. 2). The system selects the best codebook entries
depending on parameters including type of code employed, adaptive or
fixed. (See col. 9, ll. 21-32). Bit allocation and coding is optimized for each
frame based on the speech characteristics. The type classification allows the
system to assign a bit allocation to improve the perceptual qualities of the
speech. (Col. 5, ll. 23-26).
11. Gao’s system enhances perceptual quality by modifying a
decoder synthesis filter 394 using three different enhancements. One such
enhancement involves a short term spectral filter. (Col. 48, l. 57 to col. 49,
l. 17; Fig. 10). The synthesis filter 394 is cascaded with a perceptual filter
396 (FF 10).

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PRINCIPLES OF LAW
“[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). “On appeal to the Board, an applicant
can overcome a rejection by showing insufficient evidence of prima facie
obviousness . . . .” Kahn, 441 at 985-86 (Fed. Cir. 2006) (quoting In re
Rouffet, 149 F.3d 1350, 1355 (Fed. Cir. 1998).
If a person of ordinary skill can implement a predictable
variation, § 103 likely bars its patentability. For the same
reason, if a technique has been used to improve one device, and
a person of ordinary skill in the art would recognize that it
would improve similar devices in the same way, using the
technique is obvious unless its actual application is beyond his
or her skill.

KSR Int’l Co. v. Teleflex, Inc., 127 S.Ct. 1727, 1740 (U.S. 2007).
“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 applicant’s burden to precisely define their invention,
not the PTO’s.” Id.
ANALYSIS
Appellant’s and Gao’s system both process CELP codes and use
different filters for different code rates. (FF 1, 3, 4, 7, 10). The Examiner
applied Gao’s general teaching of applying different filters to different code
rates as an obvious modification of the APA, CELP layered coding system.
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(Ans. 3, 5-6, FF 1). The remaining portions of Gao’s system are not
required to support the rejection, as the Examiner reasoned. (Ans. 5-6).
Therefore, under Kahn, supra, Appellant’s general allegation that the
Gao’s and the APA systems conflict does not rise to the level of
demonstrating error in the Examiner’s position. Moreover, the Examiner
specifically noted that such a general allegation that “Gao conflicts . . .
amount[s] to a general allegation that the claims define a patentable
invention without specifically pointing out how the language of the claims
patentably distinguishes them from the references.” (Ans. 6).
Appellant proffered no specific response as to why Gao’s teachings
regarding different or weakened filters, applicable to CELP codes (FF 4),
does not similarly apply to the APA layered CELP codes (FF 1). Although
Appellant correctly notes that Gao’s system “switches among separate
coders for different bit rates,” (Br. 4), Appellant does not address the
Examiner’s findings that Gao’s system further analyzes speech within the
different coders based on other characteristics to define categories within
each coder, and also breaks the categories down to include different fixed
and adaptive codes (see Ans. 3-6, FF 10). Thus, at a minimum, Gao’s weak
filter teachings reasonably apply to the APA layered CELP systems, as
noted supra, but further, though not required for this opinion, Gao’s
teachings also reasonably imply that Gao’s system could also be adapted to
process APA layered CELP codes.
Appellant raises no other arguments with respect to claim 5.
Accordingly, under Kahn, Appellant did not demonstrate error in the
Examiner’s supported finding that Gao’s long term post-filtering (Ans. 5,
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citing col. 59, ll. 23-36, see FF 9) in combination with the APA system,
meets the claim.
Similarly, Appellant does not challenge with any specificity the
Examiner’s general finding that Gao’s weak filter teachings apply to the
APA “perceptual filters” recited in claim 3, and are involved in the APA
layered CELP coding system. (Ans. 5-6, FF 1). While Appellant does state
that Gao’s teachings apply to spectral filters (Br. 4 – citing Gao, col. 54, ll.
1-4), that particular Gao passage teaches introducing spectral filter responses
into other filters, such as Gao’s synthesis filter. (FF 7). Under Morris,
supra, Appellant’s mere denial that the prior art does not teach Appellant’s
term does meet Appellant’s burden of defining the term.
In any event, Gao’s synthesis and perceptual filters are cascaded
together (FF 6, 11). Skilled artisans would have recognized that Gao’s
teachings (see FF 7) would have suggested modifying either filter in the
chain, because the overall frequency response of the chain remains the same
regardless of which filter contains the weakened filter response (see FF 5).
Moreover, as noted supra, Appellant does not define the “perceptual
filters” recited in claim 3, but rather, discloses that a “perceptual weighting
filter” has the same form as other filters. (FF 2). However, claim 3 does not
recite “perceptual weighting filters.” Claim 3 merely recites “perceptual
filters including inverse filters.” Therefore, assuming arguendo one of skill
would not have modified Gao’s or the APA perceptual filters, the claim
reasonably embraces Gao’s synthesis filter as included in a cascaded
perceptual filter chain.
Additionally, Gao specifically refers to enhancing perceptual quality
by modifying a synthesis filter in the decoder with a weak filter (FF 11), and
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also generally discloses improving perceptual qualities of speech without
specific relation to any perceptual filter (FF 10). Such references further
imply a broad definition for “perceptual” processing or filtering that includes
Gao’s synthesis filters.
Appellant’s statement that Gao’s weakened filter teachings “relate[] to
the excitation encoding, not the decoding of claim 4” (Br. 4), fails to address
the Examiner’s finding that Gao’s decoding and encoding systems employ
similar processes (Ans. 6, FF 8). In any event, Gao specifically introduces a
weak short term spectral filter into the decoder (FF 11), contrary to
Appellant’s argument.
Gao’s system, in combination with the APA, meets claim 4 for an
additional reason. Appellant’s statement limiting Gao’s teachings to the
encoder ignores the fact that Gao’s decoding and encoding subsystems
constitute one speech compression system (FF 4). Claim 4, reciting
decoding in the preamble, does not preclude encoding. To the contrary,
similar to Gao’s system, claim 4 implies encoding occurs as a first step of
the decoding process. That is, claim 4 recites “at least two of the number of
layers . . . to form said synthesized layered encoded signal.”
As such, Gao’s weak filters in the encoder also apply to claim 4. That
is, Gao’s encoder resynthesizes speech in a feedback loop stage after
processing the speech first in several previous stages (FF 6, 7). Such
resynthesized speech implies synthesized encoded speech - as synthesized
and encoded in Gao’ initial processing stages and/or cascaded feedback
stage (see FF 5-7). Therefore, Gao reasonably suggests, in combination with
the APA layered encoded signals, “applying a short-term postfiltering to a
synthesized layered encoded signal,” as also recited in claim 4.
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The Examiner’s cumulative rationale amounts to a finding that
applying Gao’s CELP weak, different, and postfilter teachings to the APA
layered CELP system predictably improves similar devices in the same way
by applying different or the same filter processing techniques to differently
coded speech. As such, under KSR and Kahn, Appellant failed to
demonstrate error in the Examiner’s findings.
CONCLUSION
Appellant did not demonstrate that the Examiner erred in finding that
Gao’s teachings apply to the APA decoding/encoding systems, thereby
meeting the weak filter element of claim 3, the different filter element of
claim 4, and the independent postfiltering element of claim 5. Accordingly,
we sustain the 35 U.S.C. § 103 rejection of claims 3-5.
DECISION
The Examiner’s decision rejecting claims 3-5 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)(1)(iv)(2006).

AFFIRMED

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