Ex Parte Amizic et alDownload PDFPatent Trial and Appeal BoardMar 25, 201311258735 (P.T.A.B. Mar. 25, 2013) Copy Citation UNITED STATES PATENT AND TRADEMARKOFFICE 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. 11/258,735 10/26/2005 Bruno Amizic 7261 3895 7590 03/26/2013 Zenith Electronics Corporation 2000 Millbrook Drive Lincolnshire, IL 60069 EXAMINER PUENTE, EVA YI ZHENG ART UNIT PAPER NUMBER 2633 MAIL DATE DELIVERY MODE 03/26/2013 PAPER 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. PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE _____________ BEFORE THE PATENT TRIAL AND APPEAL BOARD _____________ Ex parte BRUNO AMIZIC and TYLER BROWN _____________ Appeal 2010-010273 Application 11/258,735 Technology Center 2600 ______________ Before ERIC B. CHEN, BRYAN F. MOORE, and LARRY J. HUME, Administrative Patent Judges. MOORE, Administrative Patent Judge. DECISION ON APPEAL Appeal 2010-010273 Application 11/258,735 2 This is a decision on appeal under 35 U.S.C. § 134(a) of the Final Rejection of claims 1, 4-6, 22, 25-32, 35-40, 43, and 45. App. Br. 2. Claims 33, 34, 41, 42, 46, and 47 are objected to as being dependent upon rejected claims. Id. Claims 2, 3, 7-21, 23, 24, and 44 are canceled. Id. We have jurisdiction under 35 U.S.C. § 6(b). We AFFIRM-IN-PART. INVENTION The invention is directed to timing recovery in digital receivers. See Spec. 1:12-13. Claim 25 and 35 are exemplary of the invention and are reproduced below: 1. A method of detecting a receiver timing error with respect to a received signal comprising: expanding the bandwidth of the received signal, wherein the expanding of the bandwidth of the received signal comprises determining the magnitude squared of the received signal, and wherein the expanding of the bandwidth of the received signal comprises complex conjugating the received signal and multiplying the received signal and the complex conjugated received signal; and, determining the timing error based on the bandwidth expanded received signal, wherein the timing error is determined by use of a timing error detector employing at least one delay element. 25. A method of detecting a receiver timing error with respect to a received signal comprising: expanding the bandwidth of the received signal, wherein the received signal has a period, wherein the expanding of the bandwidth of the received signal comprises expanding the bandwidth of the received signal using a delay of (n/2) times the period, and wherein n is an integer > 2; and, Appeal 2010-010273 Application 11/258,735 3 determining the timing error based on the bandwidth expanded received signal, wherein the timing error is determined by use of a timing error detector employing at least one delay element. 35. A method of detecting a receiver timing error with respect to a received signal comprising: expanding the bandwidth of the received signal; filtering the bandwidth expanded received signal with a narrow band filter so as to pass an upper band edge of the bandwidth expanded received signal and not a lower band edge of the bandwidth expanded received signal; and, determining the timing error based on the filtered bandwidth expanded received signal, wherein the timing error is determined by use of a timing error detector employing at least one delay element. REFERENCES Guilford US 5,455,847 Oct. 3, 1995 Tzou US 5,881,098 Mar. 9, 1999 Jun US 2004/0161056 Aug. 19, 2004 Kim US 2005/0141660 Jun. 30, 2005 Applicants’ Admitted Prior Art, Spec. Fig. 2; 3:5-13) (“AAPA”) REJECTIONS AT ISSUE Claims 1, 4-6, 22, 43, and 45 stand rejected under 35 U.S.C. § 103(a) as unpatentable over the combination of Jun, Guilford, and AAPA. Ans. 3-8. Claims 25, 26, and 30-32 stand rejected under 35 U.S.C. § 103(a) as unpatentable over the combination of Tzou and AAPA. Ans. 8-12. Claims 27 and 28 stand rejected under 35 U.S.C. § 103(a) as unpatentable over the combination of Tzou, AAPA, and Jun. Ans. 12. Claims 29 and 35-40 stand rejected under 35 U.S.C. § 103(a) as unpatentable over the combination of Tzou, AAPA, and Kim. Ans. 13. Appeal 2010-010273 Application 11/258,735 4 ISSUES 1. Did the Examiner err in finding that Jun and Guilford collectively teach “the expanding of the bandwidth of the received signal comprises complex conjugating the received signal and multiplying the received signal and the complex conjugated received signal,” as recited in claim 1; 2. Did the Examiner err in finding that Tzou teaches “the expanding of the bandwidth of the received signal comprises expanding the bandwidth of the received signal using a delay of (n/2) times the period,” as recited in claim 25; and 3. Did the Examiner err in finding that the combination of Tzou and Kim collectively teach “filtering the bandwidth expanded received signal with a narrow band filter so as to pass an upper band edge of the bandwidth expanded received signal and not a lower band edge of the bandwidth expanded received signal,” as recited in claim 35? ANALYSIS Appellants argue “one of ordinary skill in the art would not substitute the complex conjugate squaring process of Guilford for the squarer 408 of Jun because the signal entering the squarer 408 of Jun is not complex as indicated by formula 5 of Jun.” App. Br. 6-7. This argument is not persuasive. Appeal 2010-010273 Application 11/258,735 5 Jun teaches that the output of the adder 407, which is the magnitude squared of a received signal OQ(t), is expressed as real2 (t) + imag2 (t) = i(t)2 + q(t)2. Jun, ¶ [0052] (Formula 5). The received signal OQ(t) (shown in Formula 2) has a real and an imaginary part, where the real part is represented as real (t) = i(t)cos α + q(t)sin α, and the imaginary part is represented as imag(t) = -i(t)sin α + q(t)cos α (shown in Formula 3). Jun, ¶ [0041] (Formula 2), [0042] (Formula 3). Appellants argue “one of ordinary skill in the art would not substitute the complex conjugate squaring process of Guilford for either of the squarers 405 and 406 of Jun because, then, the purpose of the squarers 405 and 406 and the adder 407 of Jun would be impeded and frustrated as shown by formulas 4 and 5 of Jun.” App. Br. 7. Appellants further argue “one of ordinary skill in the art is not taught how [to] replace both the squarers 405 and 406 and the adder 407 of Jun with the complex conjugate squaring process of Guilford. Indeed, such a combination would not produce the same output as the output of the adder 407 of Jun and, therefore, would not be useful in Jun.” Id. Specifically, Appellants argue the Examiner’s proposed combination would not produce “these operations do not produce the desired result of i2 (t) + q2 (t) shown in Formula 5 of Jun.” Reply Br. 2. These arguments are not persuasive. The Examiner shows that using the method of Guilford, such that the magnitude of the received signal will resolve to i2 (t) + q2 (t) which is the same as the equation required by Jun in formula 5. Ans. 18. Appellants’ Reply Brief does not specifically respond to this finding by the Examiner. Additionally, we note that Appellants argue that “the respective outputs of the filters 403 and 404 of Jun are given by: real(t) = i(t)cos α + q(t)sin α Appeal 2010-010273 Application 11/258,735 6 imag(t) = i(t)sin α + q(t)cos α,” without giving a citation for this assertion. Reply Br. 2. Appellants then assert that performing a complex conjugate on these formulas will result in the following equation which is different than the equation in formula 5 of Jun: i2(t) – q2(t). Nonetheless, we accept the Examiner’s explanation of how to derive this formula, noted above, because it is based on citations to Formulas 2 and 3 of Jun, rather than an uncited formula. We find that the Examiner has shown that using the method of Guilford to replace squarer 405 and 406 and adder 407 will produce the same result as Formula 5 in Jun. Ans. 18. Therefore, the purpose of the squarers 405 and 406 and the adder 407 of Jun would not be impeded and frustrated. Appellants do not substantively argue the rejection of claims 4-6, 22, 43, and 45. Thus, for the reasons stated above, we affirm the Examiner’s decision to reject claims 1, 4-6, 22, 43, and 45. Claim 25 Appellants argue that “Tzou fails to disclose a delay element having a delay of nT/2, where n is greater than 2. Because the delay in Tzou is the symbol period T, Tzou cannot produce the signal of independent claim 25.” App. Br. 8. We are not persuaded by this argument. The law is replete with cases in which the difference between the claimed invention and the prior art is some range or other variable within the claims . . . [I]n such a situation, the applicant must show that the particular range is critical, generally by showing that the claimed range achieves unexpected results relative to the prior art range. See In re Woodruff, 919 F.2d 1575, 1578 (Fed. Cir. 1990). Appellants have made no such showing in the present case. The Specification states only that Appeal 2010-010273 Application 11/258,735 7 “[t]he delay element 56 may have a delay of, for example, 0, Tsym/2, 3Tsym/2, etc., where the period Tsym is the symbol period in the 8 VSB digital television signal according to the ATSC Digital Television Standard.” Spec, 9:18-22. This statement does not provide any reason the range is critical and in fact suggests that the delay is at least in part dictated by the ATSC Digital Television Standard. See Ans. 19. Appellants do not substantively argue the rejection of claims 26-32. Thus, for the reasons stated above, we affirm the Examiner’s decision to reject claims 25-32. Claim 35 Claim 35 recites “filtering the bandwidth expanded received signal with a narrow band filter so as to pass an upper band edge of the bandwidth expanded received signal and not a lower band edge of the bandwidth expanded received signal.” Appellants argue “the Examiner has offered no suggestion for passing the upper band edge and not the lower band edge of the signal supplied to the timing recovery circuit 62 of Tzou.” App. Br. 11. Additionally, Appellants argue that “even if a narrow band filter were used in Tzou, there is no suggestion that such a filter should be arranged to pass an upper band edge of a signal but not a lower band edge of the signal.” App. Br. 12. We are persuaded by this argument. The Examiner asserts that Kim teaches a conventional timing error recovery system. Ans. 20. The Examiner then notes that: The prefilter of the instant invention is a narrow band filter that passes an upper band edge of the signal and not a lower band edge of the signal (as claimed). Since Kim discloses a timing recovery system that has an identical structure as the timing Appeal 2010-010273 Application 11/258,735 8 recovery system of the instant invention, it would be obvious to one skilled in the art to recognize that the prefilter (302) of Kim would need to perform the same function as the prefilter (44) of the instant invention. That is, the prefilter of Kim is also a narrow band filter that passes an upper band edge of the signal and not a lower band edge of the signal. Ans. 20-21. Because the Examiner uses the present invention as the motivation to use a narrow band filter that passes an upper band edge of the signal and not a lower band edge of the signal, the record indicates that the Examiner used impermissible hindsight in rejecting claim 35. See In re Warner, 379 F.2d 1011, 1017 (CCPA 1967) (“A rejection based on section 103 clearly must rest on a factual basis, and these facts must be interpreted without hindsight reconstruction of the invention from the prior art”). The Examiner also argues that “Kim further states that a convergence characteristic of the Gardner timing error detector depends on a gain of an upper band edge of a spectrum positioned at a point of one half a symbol frequency (Para [0029]).” Ans. 21. However, this paragraph of Kim only suggests that the detector depends on a gain of an upper band edge but does not state that the input of detector must not contain a lower band edge of the signal as required by claim 35. See Reply Br. 4. Thus, as noted above, the Examiner’s only basis for finding that the prior art teaches passing the upper band edge and not the lower band edge of the signal to the timing error circuit. Therefore, we cannot sustain the Examiner’s rejection of claim 35, or claims 36-40 that depend from claim 35. Appellants argue “[d]ependent claim 29 is not unpatentable over Tzou in view of AAPA and further in view of Kim for similar reasons [as claim 35].” App. Br. 12. We note that claim 29 does not contain the limitation Appeal 2010-010273 Application 11/258,735 9 discussed in association with claim 35, so, as noted above, claim 29 falls with claim 25 from which it depends. DECISION The Examiner’s decision to reject claims 1, 4-6, 22, 25-32, 43, and 45 is affirmed. The Examiner’s decision to reject claims 35-40 is reversed. 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-IN-PART tj Copy with citationCopy as parenthetical citation