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`UNITED STATES PATENT AND TRADEMARK OFFICE
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`_________________
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`
`_________________
`
`DEXCOM, INC.,
`Petitioner,
`
`v.
`
`ABBOTT DIABETES CARE INC.,
`Patent Owner.
`
`
`
`U.S. Patent No.: 11,298,056
`
`Title: METHODS AND SYSTEMS FOR EARLY SIGNAL ATTENUATION
`DETECTION AND PROCESSING
`
`_________________
`
`DECLARATION OF BRIAN D. GROSS
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`Page 1
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`TABLE OF CONTENTS
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`Page
`INTRODUCTION AND ENGAGEMENT .................................................... 5
`I.
`BACKGROUND AND QUALIFICATIONS ................................................. 6
`II.
`III. SCOPE OF OPINION ..................................................................................... 8
`IV. MATERIALS CONSIDERED AND INFORMATION RELIED UPON
`REGARDING THE ’056 PATENT ................................................................ 9
`A.
`LIST OF EXHIBITS ............................................................................. 9
`V. UNDERSTANDING OF PATENT LAW ....................................................11
`VI. THE ’056 PATENT .......................................................................................15
`A.
`Specification ........................................................................................15
`B.
`Prosecution History .............................................................................18
`VII. STATE-OF-THE-ART AND LEVEL OF SKILL IN THE ART .................18
`A.
`State-of-the-Art ...................................................................................18
`1.
`Sensors With Working and Counter Electrodes .......................19
`2.
`Sensor Sensitivity In Calibration ..............................................21
`3. Microprocessor Computations ..................................................23
`4.
`Bluetooth Communication ........................................................27
`B. Ordinary Level Of Skill In The Art .....................................................29
`VIII. GROUND 1: CLAIM 13 IS OBVIOUS OVER PATEL-2009 AND
`PARADIGM® REAL-TIME ........................................................................35
`A.
`Patel-2009 (EX1212) Is Supported By Its Provisional Application
`(EX1214) .............................................................................................35
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`B.
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`C.
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`The Medtronic Diabetes Website’s Publication Of Webpages And
`Other Information On Paradigm® REAL-Time (EX1211) Was
`Publicly Accessible And Known By A POSITA ................................43
`Patel-2009 And Paradigm® Real-Time Disclose Glucose Monitoring
`Systems Easily Combined, And The Motivation To Do So With An
`Expectation Of Success .......................................................................45
`1.
`Patel-2009 .................................................................................45
`2.
`Paradigm® REAL-Time ...........................................................48
`3.
`Combination of Patel-2009 and Paradigm® REAL-Time .......49
`4. Motivation To Combine And Expectation Of Success.............51
`D. Ground 1 Claim Mappings ..................................................................54
`1.
`Claim 1 ......................................................................................54
`a)
`[1.A] (preamble) .............................................................54
`b)
`[1.B] ................................................................................57
`c)
`[1.C] ................................................................................59
`d)
`[1.D] ................................................................................60
`e)
`[1.E] ................................................................................62
`f)
`[1.F].................................................................................65
`g)
`[1.G] ................................................................................66
`h)
`[1.H] ................................................................................68
`i)
`[1.I] .................................................................................68
`j)
`[1.J] .................................................................................70
`k)
`[1.K] ................................................................................70
`l)
`[1.L] ................................................................................72
`Claim 13 ....................................................................................74
`
`2.
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`IX. GROUND 2: CLAIM 29 IS OBVIOUS OVER PATEL-2009,
`PARADIGM® REAL-TIME, AND GOLDSMITH ......................................76
`A. Goldsmith (EX1251) ...........................................................................76
`B.
`Combination of Patel-2009, Paradigm® REAL-Time, And Goldsmith
` .............................................................................................................82
`1. Motivation to Combine and Expectation of Success ................85
`C. Ground 2 Claim Mappings ..................................................................89
`1.
`Claim 29 ....................................................................................89
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`I, Brian D. Gross, BSEE, M.Sc., do hereby declare as follows:
`
`I.
`
`INTRODUCTION AND ENGAGEMENT
`
`1. My name is Brian D. Gross, and I have been retained as an independent
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`expert on behalf of Dexcom, Inc. in connection with the above-captioned Petition
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`for Inter Partes Review (“IPR”) to provide my analyses and opinions on certain
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`technical issues related to U.S. Patent No. 11,298,056 (hereinafter “the ’056
`
`Patent”). Specifically, I have been asked to provide my opinions regarding whether
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`claims 13 and 29 of the ’056 Patent would have been obvious to a person having
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`ordinary skill in the art (“POSITA”) as of April 2009. After reviewing the prior art
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`discussed herein, it is my opinion that each of claims 13 and 29 of the ’056 Patent
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`would have been obvious to a POSITA.
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`2.
`
`I am being compensated at my usual and customary rate for the time I
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`spent in connection with this IPR. My compensation is not affected by the outcome
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`of this IPR.
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`3.
`
`On July 24, 2023, I submitted a declaration with testimony in support
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`of an IPR Petition challenging claims 1-12, 14-28, and 30 of the ’056 Patent. My
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`testimony in sections II. Background and Qualifications (¶¶4-8 below), IV. Materials
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`Considered and Information Relied upon Regarding The ’056 Patent (¶¶10-11
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`below), V. Understanding of Patent Law (¶¶12-24 below), VI. The ’056 Patent
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`(¶¶25-30 below), VII. State-of-the-Art and Level of Skill in the Art (¶¶31-61 below)
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`are substantively identical to corresponding paragraphs of my July 24, 2023,
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`declaration. In addition, subsections VIII.A through VIII.D.1 of Ground 1 (¶¶62-115
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`below) are substantively identical to corresponding paragraphs of my July 24, 2023,
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`declaration. While section VIII.D.2 (¶¶116-118 below) relies on analysis and
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`explanation of the prior art previously presented in my July 2023 declaration, herein
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`I present that analysis and explanation in the context of claim 13. Finally, section IX
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`(¶¶119-147 below) on claim 29 consist of testimony not previously presented in my
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`July 24, 2023, declaration.
`
`II. BACKGROUND AND QUALIFICATIONS
`
`4.
`
`Among other qualifications elaborated in my CV (EX1209), I receive
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`my Bachelor of Science in Electrical and Biomedical Engineering (BSEE) in 1990
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`and my Masters of Science in Biomedical Engineering (M.Sc.) in 1991.
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`5.
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`In 1991 and 1992, I worked as a scientist in product development
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`engineering at VivaScan. At VivaScan, my work included designing and building
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`microprocessor-controlled
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`instrumentation
`
`in many cases,
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`from discrete
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`components. The efforts at VivaScan focused on physiological monitoring and
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`included research and development related to determining glucose and other analytes
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`in the blood as manifest U.S. Patent No. 5,372,135 (“the ’135 Patent”) for “Blood
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`constituent determination based on differential spectral analysis” of which I am a
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`co-inventor.
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`6.
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`From 2003 through 2013, I was co-investigator of a bioengineering
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`research partnership with the Massachusetts Institute of Technology focused on ICU
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`patient monitoring and including the development and application of physiological
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`monitoring concepts and algorithms.
`
`7.
`
`From 2006 through 2014, I was a Principal Scientist of Patient Care and
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`Monitoring Solutions at Philips where my work related to physiological monitoring.
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`For example, in February 2008, some of my work on recognizing that gaps in
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`monitored data due to poor network quality could be resolved by caching missed
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`data and transmitting this data when sufficient bandwidth became available was filed
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`as U.S. Provisional Application 61/032,532 on “optimizing physiological
`
`monitoring based on available but variable signal quality,” which later became U.S.
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`Patent Application 12/918,822 and published as U.S. Publication 2011/0002223
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`related to “physiological monitoring over a healthcare network.” From 2014 to 2022,
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`I was a Fellow Scientist and Clinical System Architect at Philips where I taught,
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`trained, mentored, and supervised, members of the organization with less
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`experience, as well as drove risk management and design tradeoff decisions for the
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`Businesses and Research groups.
`
`8.
`
`In 2014 I was appointed by the International Standards Association to
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`serve on the IEC-TC62/SC 62D/JWG 22 as a technical and clinical expert in medical
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`device design. There I participated and led multi-national and multi-domain experts
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`in drafting global safety standards pertaining to medical devices and their design. As
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`a final example of my experience, I participated in technical and clinical research,
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`and co-authored scores of papers including an abstract on how “delayed intravenous
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`insulin therapy initiation is associated with mortality in the ICU,” which was
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`presented to the SCCM 40th Critical Care Congress in 2011.
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`III. SCOPE OF OPINION
`
`9.
`
`I have been asked to provide my opinions regarding whether claims 13
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`and 29 of the ’056 patent would have been unpatentable to a person of ordinary skill
`
`in the art (POSITA) as of April 2009 in view of:
`
`•
`
`•
`
`U.S. Patent Publication 2009/0085768 to Patel (EX1212, “Patel-
`
`2009”);
`
`An FAQ webpage, features and benefits fact sheet, and sensor features
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`user guide for the Medtronic MiniMed Paradigm® REAL-Time
`
`System archive of the Medtronic Diabetes website in October 2007
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`(EX1211, “Paradigm® REAL-Time”); and
`
`•
`
`U.S. Patent Publication No. 2007/0093786 (EX1251, “Goldsmith”).
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`IV. MATERIALS CONSIDERED AND
`INFORMATION RELIED UPON REGARDING THE ’056 PATENT
`In preparing this declaration, I have reviewed the following materials
`10.
`
`bearing Exhibit Nos. that I understand are being referenced in the IPR which this
`
`
`
`declaration accompanies:
`
`A. LIST OF EXHIBITS
`
`1209
`1211
`
`Description
`No.
`1201 U.S. Patent No. 11,298,056 (“the ’056 Patent”)
`Excerpts from Prosecution File History of U.S. Patent
`1202
`Application No. 17/411,154 (“Harper ’154 file history”)
`Curriculum Vitae of Brian Gross
`Exhibits A and B to Affidavit of Nathaniel E Frank-White
`(“Paradigm® REAL-Time Archive”)
`1212 U.S. Patent Application Publication No. 2009/0085768 to Patel
`et. al. (“Patel-2009”)
`1214 U.S. Provisional Patent Application No. 60/976,886 (“Patel-
`2009 provisional”)
`1215 U.S. Patent Application Publication No. 2008/0119705 to Patel
`et. al. (“Patel-2008”)
`1217 U.S. Patent No. 6,641,533 to Causey et. al. (“Causey”)
`1219 U.S. Patent Application Publication No. 2006/0202859 to
`Mastrototaro et. al. (“Mastrototaro”)
`1222 U.S. Patent Application Publication No. 2004/0122353 to
`Shahmirian et al. (“Shahmirian”)
`1225 McGarraugh, Geoffrey. “The chemistry of commercial
`continuous glucose monitors.” Diabetes technology &
`therapeutics 11.S1 (2009): S-17.
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`1227
`
`1226 U.S. Patent Application Publication No. 2004/0193025 to Steil et
`al.
`Choleau, C., et al. “Calibration of a subcutaneous amperometric
`glucose sensor implanted for 7 days in diabetic patients: Part 2.
`Superiority of the one-point calibration method.” Biosensors and
`Bioelectronics 17.8 (2002): 647-654.
`1228 Velho, G., et al. “In vivo calibration of a subcutaneous glucose
`sensor for determination of subcutaneous glucose
`kinetics.” Diabetes, American Diabetes Association 1.3 (1988):
`227-233.
`1229 Mastrototaro, John J. “The MiniMed continuous glucose
`monitoring system.” Diabetes technology & therapeutics 2.1,
`Supplement 1 (2000): 13-18.
`1230 U.S. Patent No. 6,424,847 to Mastrototaro et al.
`Poitout, V., et al. “A glucose monitoring system for on line
`1231
`estimation in man of blood glucose concentration using a
`miniaturized glucose sensor implanted in the subcutaneous tissue
`and a wearable control unit.” Diabetologia 36 (1993): 658-663.
`1232 U.S. Patent Application Publication No. 2006/0224109 to Steil et
`al.
`1233 Keenan, D. Barry, et al. “Delays in minimally invasive
`continuous glucose monitoring devices: a review of current
`technology.” Journal of diabetes science and technology 3.5
`(2009): 1207-1214.
`1235 Armstrong, Siân. “Wireless connectivity for health and sports
`monitoring: a review.” British journal of sports medicine 41.5
`(2007): 285-289.
`Pantelopoulos, Alexandros, and Nikolaos Bourbakis. “A survey
`on wearable biosensor systems for health monitoring.” 2008 30th
`Annual International Conference of the IEEE Engineering in
`Medicine and Biology Society. IEEE, 2008.
`Excerpts from Diabetes forecast, November 2007
`Excerpts from Diabetes forecast, August 2007
`
`1236
`
`1237
`1238
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`1239
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`1240
`
`
`
`Buckingham, Bruce, Kimberly Caswell, and Darrell M. Wilson.
`“Real-time continuous glucose monitoring.” Current Opinion in
`Endocrinology, Diabetes and Obesity 14.4 (2007): 288-295.
`Buckingham, Bruce. “Clinical overview of continuous glucose
`monitoring.” Journal of Diabetes Science and Technology 2.2
`(2008): 300-306.
`Excerpts from Smith, Steven W. The scientist and engineer’s
`guide to digital signal processing. California Technical Pub.,
`1997.
`Shenoi, Belle A. Introduction to digital signal processing and
`filter design. John Wiley & Sons, 2006.
`Breton, Marc D., et. al. “Optimum Subcutaneous Glucose
`Sampling and Fourier Analysis of Continuous Glucose
`Monitors.” Journal of Diabetes Science and Technology 2.3
`(2008): 495-500.
`Burge, Mark R., et. al. “Continuous Glucose Monitoring: The
`Future of Diabetes Management.” Diabetes Spectrum 21.2
`(2008): 112-119.
`1251 U.S. Patent Application Publication No. 2007/0093786 to
`Goldsmith and Hayes (“Goldsmith”).
`
`1242
`
`1243
`
`1245
`
`1246
`
`11.
`
`I have also relied on my professional experience in formulating the
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`opinions expressed in this declaration.
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`V. UNDERSTANDING OF PATENT LAW
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`12.
`
`I am not an attorney. For the purposes of this declaration, I have been
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`informed about certain aspects of the law that are relevant to my opinions. My
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`understanding of the law was provided to me by the Petitioner’s attorneys.
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`13.
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`I understand that when considering the scope of the claims of a patent
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`that the patent claim terms should generally be given the ordinary meaning that the
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`terms would have to a person of ordinary skill in the art in question after reading the
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`patent as of the earliest claimed priority date.
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`14.
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`I understand that the person of ordinary skill in the art is deemed to read
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`the claim term not only in the context of the particular claim in which the term
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`appears, but in the context of the entire patent, including the specification. I further
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`understand that the principal considerations regarding the scope and meaning of the
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`claims are the plain language of the claim (including the surrounding claim language
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`and context), the patent specification, and the prosecution history. I understand that
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`while a claim is to be read in light of the specification, one must generally avoid
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`importing limitations into the claim from the specification. I am also informed that
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`the prosecution history can often inform the meaning of the claim by demonstrating
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`how the inventor understood the invention and whether the inventor limited the
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`invention in the course of prosecution, making the claim scope narrower than it
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`would otherwise be. I applied these understandings when considering the scope and
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`meaning of the claims of the ’056 patent.
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`15.
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`I understand that a prior art reference anticipates an asserted claim, and
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`thus renders the claim unpatentable, if all elements of the claim are disclosed in that
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`prior art reference, either explicitly or inherently (i.e., necessarily present or
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`implied).
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`16.
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`I further understand that a claim is unpatentable if it would have been
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`obvious. Obviousness of a claim requires that the claim would have been obvious
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`from the perspective of a POSITA at the time the alleged invention was made. I
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`understand that a claim could have been obvious from a single prior art reference or
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`from a combination of two or more prior art references.
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`17.
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`I understand that an obviousness analysis requires an understanding of
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`the scope and content of the prior art, any differences between the alleged invention
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`and the prior art, and the level of ordinary skill in evaluating the pertinent art.
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`18.
`
`I further understand that a claim would have been obvious if it unites
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`old elements with no change to their respective functions, or merely substitutes one
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`element for another known in the field, and that combination yields predictable
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`results. While it may be helpful to identify a reason for this combination, I
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`understand that there is no strict requirement of finding an express teaching,
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`suggestion, or motivation to combine within the references. When a product is
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`available, design incentives and other market forces can prompt variations of it,
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`either in the same field or different one. If a POSITA can implement a predictable
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`variation, obviousness likely bars its patentability. For the same reason, if a
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`technique has been used to improve one device and a POSITA would recognize that
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`it would improve similar devices in the same way, using the technique would have
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`been obvious. I understand that a claim would have been obvious if common sense
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`directs one to combine multiple prior art references or add missing features to
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`reproduce the alleged invention recited in the claims.
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`19.
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`I further understand that certain factors may support or rebut the
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`obviousness of a claim. I understand that such secondary considerations include,
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`among other things, commercial success of the patented invention, skepticism of
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`those having ordinary skill in the art at the time of invention, unexpected results of
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`the invention, any long-felt but unsolved need in the art that was satisfied by the
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`alleged invention, the failure of others to make the alleged invention, praise of the
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`alleged invention by those having ordinary skill in the art, and copying of the alleged
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`invention by others in the field. I understand that there must be a nexus—a
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`connection—between any such secondary considerations and the alleged invention.
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`I also understand that contemporaneous and independent invention by others is a
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`secondary consideration tending to show obviousness.
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`20.
`
`I am not aware of any allegations by the named inventors of the ’056
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`patent or any assignee of the ’056 patent that any secondary considerations tend to
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`rebut the obviousness of any Challenged Claim of the ’056 patent.
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`21.
`
`I understand that in considering obviousness, it is important not to
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`determine obviousness using the benefit of hindsight derived from the descriptions
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`found in the patent being considered.
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`22.
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`I understand that other challenges to the patentability of a patent,
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`including patent ineligibility, enablement, written description, and definiteness or
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`clarity of claim language, cannot be raised in IPR proceedings before the Board.
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`23.
`
`I understand that Petitioner has the burden of proving unpatentability
`
`by a preponderance of evidence, which means that the claims are more likely than
`
`not unpatentable.
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`24. The analysis in this declaration is in accordance with the above-stated
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`legal principles.
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`VI. THE ’056 PATENT
`
`25. As part of my analysis, I reviewed and considered the ’056 patent
`
`(EX1201) titled “Methods and Systems for Early Signal Attenuation Detection and
`
`Processing” which I understand issued from U.S. Application 17/411,154 on April
`
`12, 2022. The following highlights general aspects of the ’056 patent and is not
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`meant to describe my full understanding of the patent or its prosecution history.
`
`A.
`
`Specification
`
`26. The ’056 patent describes an analyte monitoring system including
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`a sensor unit, a data processing and transmitter unit, and a primary receiver unit.
`
`(EX1201, 4:56-61.)
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`27. The transmitter unit “receives analyte related sensor data” from the
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`sensor and transmits this data to the receiver unit. (EX1201, 11:27-37.) The
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`transmitter unit is described as operating on approximate radio frequency bands of
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`315-322MHz or 400-470MHz. (EX1201, 9:15-22.) The communication link
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`between the transmitter and receiver is discussed as including various infrared,
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`Bluetooth®, 802.11x, or other wireless communication protocols. (EX1201, 7:25-
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`33.)
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`28. The ’056 patent defines “analyte related sensor data herein and
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`throughout [the] specification” as both “current signal received from the analyte
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`sensor” and “current signal which has undergone … processing routines including,
`
`for example filtering, clipping, digitizing,” encoding, conditioning, or further
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`processing. (EX1201, 11:37-44, 14:21-23.) For example, unprocessed or
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`uncalibrated sensor data is processed with “calibration data such as [a] sensitivity
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`ratio.” (EX1201, 12:54-61.) Calibration “ensure[s] the analyte related data signals
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`… are correctly converted to corresponding analyte levels,” but various conditions
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`render calibration unsuitable. (EX1201, 10:62-66, 11:6-8.) The ’056 patent then
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`describes that “when a scheduled calibration event fails …, the output display of the
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`processed, calibrated sensor data is disabled” resulting in a gap “where the analyte
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`monitoring system was not properly calibrated [and] analyte related sensor data was
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`not processed:”
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`(EX1201, 12:32-45, Fig. 7A.) The ’056 patent specification describes backfilling
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`gaps by processing unprocessed sensor data with the sensitivity ratio from a
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`subsequent calibration:
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`(EX1201, 12:47-13:5, Fig. 7B.)
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`B.
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`29.
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`Prosecution History
`
`I understand that the ’056 Patent (EX1201) issued from U.S. Patent
`
`Application No. 17/411,154 filed August 25, 2021 (EX1202), which claims priority
`
`to the April 29, 2009 filing of Provisional Application 61/173,600 through a series
`
`of continuation applications.
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`30.
`
` I have reviewed U.S. Patent Application No. 17/411,154 and its
`
`prosecution file history. (EX1202).
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`VII. STATE-OF-THE-ART AND LEVEL OF SKILL IN THE ART
`
`A.
`
`State-of-the-Art
`
`31. The ’056 patent pertains to glucose monitoring systems, including:
`
`•
`
`•
`
`•
`
`•
`
`two and three-electrode sensors that generate analyte signals
`
`(EX1201, 1:34-37);
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`calibration to determine a “sensitivity ratio” that is used to
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`convert sensor data to analyte levels (EX1201, 12:47-61);
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`signal processing
`
`(e.g.,
`
`filtering,
`
`clipping, digitizing,
`
`conditioning) (EX1201, 5:58-64, 11:37-44); and
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`RF transmission (e.g., 315-322MHz, 400-470MHz, Bluetooth,
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`802.11x/WLAN). (EX1201, 7:25-33, 9:15-22.)
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`As discussed in this section, these were each well-known, fundamental concepts of
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`glucose monitoring by April 2009. (See Paragraphs 32-49.)
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`1.
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`Sensors With Working and Counter Electrodes
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`32. Analyte sensors with “two or three-electrode (work, reference, and
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`counter electrodes) configuration[s]” were well known to a POSITA by April 2009.
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`This knowledge is illustrated by the references in paragraphs 33-35 below.
`
`33. For example, a May 2009 article on “The Chemistry of Commercial
`
`Continuous Glucose Monitors” by McGarraugh provides:
`
`•
`
`a typical glucose sensor “includes three electrodes: a GOx working
`
`electrode, a counter electrode, and an Ag/AgCl reference electrode”
`
`(EX1225, S-19); and
`
`•
`
`each of the Medtronic Guardian REAL-Time, DexCom™ STS™-7,
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`and Abbot FreeStyle Navigator® “measure[d] the current flowing from
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`an oxidation (electron-producing) reaction at a working electrode to a
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`reduction (electron-consuming) reaction at a counter electrode.”
`
`(EX1225, S-19.)
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`34. Medtronic’s U.S. Publication 2006/0202859 to Mastrototaro discloses
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`a sensor with three sensor electrodes 20:
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`(EX1219, [0045], Fig. 6 (annotated in red).)
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`35. Medtronic’s U.S. Publication 2004/0193025 labels the counter (CNT)
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`electrode in a similar figure:
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`(EX1226, [0038], Fig. 4 (annotated in red).)
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`36. Therefore, it is my opinion that skilled artisans were familiar with
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`sensor configurations including work and counter electrodes.
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`2.
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`Sensor Sensitivity In Calibration
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`37. Sensor calibration was well known to a POSITA by April 2009. As
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`illustrated by the references in paragraphs 38-39 below, glucose sensor calibration
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`was typically performed by using blood glucose reference values to determine a
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`sensitivity coefficient or ratio between sensor current and glucose concentration,
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`which was later applied to convert sensor current to glucose concentration.
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`38. For example, a 1988 article titled “In vivo calibration of a subcutaneous
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`glucose sensor for determination of subcutaneous glucose kinetics” by Valho et. al.
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`“defined a method for calibrating in vivo a subcutaneous glucose sensor” as
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`“determining, for a given sensor, the variation in the current corresponding to a
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`change in BG [(blood glucose)] concentration. This in vivo sensitivity coefficient
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`was then used to determine from the sensor output an apparent subcutaneous glucose
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`concentration…” (EX1228, 227; see also 228 (discussing the sensitivity coefficient
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`as the “ratio between decrease in the sensor current and the decrease in glucose
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`concentration.”) “The in vivo sensitivity coefficient” is then “used to calculate
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`apparent subcutaneous glucose level” by dividing “current by the sensitivity
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`coefficient” after subtracting baseline (I0). (EX1228, 228-229.) Similarly, a 2002
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`article on “Calibration of a subcutaneous amperometric glucose sensor implanted for
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`7 days in diabetic patients Part 2: Superiority of the one-point calibration method”
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`by Choleau et. al. provides:
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`[T]he sensor sensitivity S is determined from a single blood
`glucose determination as the ratio between the concomitant
`sensor current I and the blood glucose concentration G.
`Subsequently, the glucose concentration can be estimated at any
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`time from the current I as 𝐺𝐺(𝑡𝑡)=𝐼𝐼(𝑡𝑡)/𝑆𝑆.
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`(EX1227, 648.)
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`39. According to a 2000 article titled “The MiniMed Continuous Glucose
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`Monitoring System” by Mastrototaro, the Medtronic CGMS associates interstitial
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`glucose concentration to electrical current in nanoamperes (nA) using a calibration
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`based on blood glucose readings. (EX1229, S-15.) Consistently, Medtronic’s U.S.
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`Patent 6,424,847 provides that calibration involves calculating a calibration factor
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`called a sensitivity ratio (SR) (blood glucose level/Valid ISIG value) … used to
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`convert the Valid ISIG value (Nano-Amps) into a blood glucose level (mg/dl or
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`mmol/l).” (EX1230, 11:28-33.)
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`40. Therefore, skilled artisans knew that calibration is associated with the
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`sensitivity of the glucose sensor and were familiar with using blood glucose
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`reference values to determine a sensor sensitivity ratio and with applying this
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`sensitivity ratio to convert sensor signals to glucose concentrations. A POSITA knew
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`that both the data relied on to calibrate the sensor and the resulting coefficients used
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`to convert sensor signals to glucose concentrations are associated with the sensitivity
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`of the glucose sensor.
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`3. Microprocessor Computations
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`41. Processing sensor signals with various algorithms and processing
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`routines was well known to a POSITA by 2009. This knowledge is illustrated by the
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`references in paragraphs 42-45 below.
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`42. As discussed in an article titled “A glucose monitoring system for on
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`line estimation in man of blood glucose concentration using a miniaturized glucose
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`sensor inserted in the subcutaneous tissue and a wearable control unit” by Poitout et
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`al., the necessity of sampling, filtering, storing, and processing glucose sensor
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`electrical current values before conversion to real-time glucose concentrations was
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`well known by 1993. (EX1231, 661.) For example, early glucose monitors had
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`memory to store 8,000 electrical current values and used algorithm procedures to
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`filter and process signals. (EX1231, 659, 662.)
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`43. By the early to mid-2000’s, Medtronic had developed more advanced
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`procedures for smoothing, filtering, storing, and processing sensor electrical current
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`signals. For example, Medtronic’s U.S. Patent 6,641,533 to Causey used a sensor
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`monitor and microprocessor to smooth and store signals received from the sensor
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`and to determine corresponding analyte levels. (EX1217, 22:18-22.) Meanwhile,
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`Medtronic’s U.S. Publication 2006/0224109 provides that before filtering and
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`calibration, sensor signals are processed from analog current (Isig) to digital sensor
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`values (Dsig) which are stored in a buffer. (EX1232, [230].)
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`44. A 2009 article titled “Delays in Minimally Invasive Continuous
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`Glucose Monitoring Devices: A Review of Current Technology” by Keenan et al.,
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`the Medtronic Guardian RT used a “seventh-order finite impulse response filter …
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`decimated to a 5-minute sample time interval” resulting in 8.25 minutes delay to
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`smooth the sensor’s electrical current signal with a moving average. (EX1233,
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`1211.) Similarly, Medtronic’s U.S. Patent 6,424,847 provides for sampling electrical
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`current every 10 seconds and storing averaged sampling intervals in memory.
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`(EX1230, 8:42-60.) Finally, a 2008 article titled “Optimum Subcutaneous Glucose
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`Sampling and Fourier Analysis of Continuous Glucose Monitoring” by Breton et al.
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`computed the maximum sampling frequency (i.e., Nyquist Rate) for accurately
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`determining blood glucose from interstitial glucose accounting for noise as longer
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`than 5 minute and optimally 18 minutes. (See also EX1245, 497-98.) A POSITA
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`would recognize that these filtering, averaging, and sampling procedures would
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`induce a lag (e.g., 8.25 minutes) between when sensor data is measured and when
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`processed glucose data is displayed and that data would need to be stored in memory
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`at various points during processing. A POSITA would also recognize that data could
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`be scheduled to update in accordance with one of more sampling intervals (e.g.,
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`every 10 seconds, minute, or 5 minutes, 18 minutes, etc.).
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`45. A POSITA would have known to store sensor signals or other data used
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`by a processor in performing any of the processing routines described above. For
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`example, Chapter 28 of the 1997 publication Scientist and Engineer’s Guide to
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`Digital Signal Processing by Steven W. Smith acknowledges the role of memory in
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`executing processing routines on page 509: “One of the biggest bottlenecks in
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`ex