Board of Patent Appeals and Interferences
Patent and Trademark Office (P.T.O.)
*1 EX PARTE CHARLES H. LOGAN
Appeal No. 89-2047
February 20, 1991
Application for Patent filed August 6, 1986, Serial No. 06/893,835. Apparatus And Method For Inspiration Detection.
Edward W. Bulchis for appellant
Supervisory Patent Examiner--Kyle L. Howell
Before Thomas, Hairston and Martin
This is a decision on an appeal under 35 U.S.C. § 134 from the examiner's rejection of claims 1-26, all of the claims in the application. [FN1]
The subject matter to which the invention relates is readily apparent from claim 1:
1. An apparatus for detecting inspiration of a patient in response to a time varying signal representative of the patient's respiration comprising:
means for establishing a baseline level for said respiration signal which falls between the peak to peak variations of said respiration signal;
means for establishing a trigger level for said respiration signal representative of inspiration;
means for generating inspiration trigger signals in response to selected crossovers of said trigger level by said respiration signal;
means for automatically detecting shifts in the baseline level of said respiration signal; and
Claims 1-26 stand rejected for failing to satisfy the enablement requirement of § 112, first paragraph.
Claims 1-26 also stand rejected under § 101 as directed to nonstatutory subject matter.
Reference may be made to the answers and the briefs for the details of the examiner's and the appellant's positions.
For the following reasons, we will not sustain either of the examiner's rejections.
Considering first the § 101 rejection, the examiner's position is stated as follows at pages 4 and 5 of the answer:
The method and apparatus disclosed and claimed reside solely in the operation of a computer program. (ie. P-code). The claims indirectly recite mathematical algorithms. For example, the method and "apparatus" for establishing baseline levels, trigger levels, etc., are all based upon mathematical relationships as set forth in the specification. Thus, the issue is whether the claims as a whole merely recites [sic] a mathematical algorithm, or method of calculation. Since there is no post-solution activity recited, the claims as a whole must be characterized as merely a computer program for calculating baseline shifts and/or interpreting results of an electrical signal and is [sic, are] therefore non-statutory. The only mode of practicing the claimed process is by appropriately programming a digital computer. The computer is claimed not in terms of a specific instruction set, but alternatively as a series of steps broadly defining what the program is designed to accomplish. The specific end use recited in the preambles does not limit the subject matter as a whole so as to avoid the 101 rejection, since the subject matter as a whole operates only on a signal gathered by elements not a part of the invention. In other words, the sole disclosure is in P-code for making computations upon an input signal.
*2 At the outset, we note it is well settled that "[t]he fact that the claimed process is performed on a computer is not a proper basis for [a § 101] rejection." In re Gelnovatch, 595 F.2d 32, 36-37, 201 USPQ 136, 141 (CCPA1979), citing with approval In re Chatfield, 545 F.2d 152, 191 USPQ 730 (CCPA1976); In re Deutsch, 553 F.2d 689, 193 USPQ 645 (CCPA1977); and In re Johnson, 589 F.2d 1070, 200 USPQ 199 (CCPA1978). "While a program may configure a computer in a manner to carry out a process, it is the process, i.e., what the computer does, which is the subject of examination under 35 USC 101, et seq." Gelnovatch, supra at 37, 201 USPQ at 141. "[T]here is no reason for treating a computer differently from any other apparatus employed to perform a recited process step." Johnson, supra at 1081 n. 12, 200 USPQ at 211 n. 12. Consequently, as regards the question of whether claims are directed to statutory or nonstatutory subject matter, it is immaterial whether the claimed process is disclosed as implemented by a programmed computer or by hardware.
The two-step test for non-statutory subject matter was set forth in In re Meyer, 688 F.2d 789, 795, 215 USPQ 193, 198 (CCPA1982), as follows:
In considering a claim for compliance with 35 USC 101, it must be determined whether a scientific principle, law of nature, idea, or mental process, which may be represented by a mathematical algorithm, is included in the subject matter of the claim. If it is, it must then be determined whether such principle, law, idea, or mental process is applied in an invention of the type set forth in 35 USC 101. This is consistent with In re Freeman, 573 F.2d 1237, 197 USPQ 464 (CCPA1978), as modified by In re Walter, 618 F.2d 758, 205 USPQ 397 (CCPA1980) [footnote omitted], and the more recent decisions by this court in In re Pardo, [684 F.2d 912], 214 USPQ 673 (CCPA ... 1982) and In re Abele, [684 F.2d 902], 214 USPQ  (CCPA ... 1982).
Thus, the first step in our analysis is to determine whether appellant's claims indirectly recite a "mathematical algorithm," as the examiner contends. As explained below, we conclude that they do not.
A mathematical algorithm is a "procedure for solving a given type of mathematical problem." Gottschalk v. Benson, 409 U.S. 63, 175 USPQ 673, 674 (1972); Diamond v. Diehr, 450 U.S. 175, 209 USPQ 1, 8 (1981). Mathematical algorithms include mathematical equations and formulas for calculating a numerical output value from a number of numerical input values, whether directly or indirectly claimed. A mathematical formula or equation is directly claimed when it is expressed in the claim by means of mathematical symbols, as in Parker v. Flook, 437 U.S. 584 (1978), and Diehr, supra. Indirect recitation can occur in either of two ways. The first, discussed in In re Freeman, 573 F.2d 1237, 1246, 197 USPQ 464, 471 (CCPA1978), is when a claim recites a mathematical formula or equation in terms of prose equivalents for mathematical symbols (e.g., the term "add" instead of the symbol "+"). The second is when the specification indicates a claimed step (e.g., "determining" or "cross-correlating") is implemented using a particular mathematical equation or formula. Johnson, supra at 1078, 200 USPQ at 208; In re Sherwood, 613 F.2d 809, 818, 204 USPQ 537, 545 (CCPA1980).
*3 Mathematical algorithms are not, however, limited to mathematical formulas and equations for calculating one or more numerical output values from one or more numerical input values. As noted in Gelnovatch, supra at 38, 201 USPQ at 142, the mathematical algorithm in Benson was a "computational procedure rather than merely a simple or complex mathematical formula." The court further noted, id. at 39, 201 USPQ at 143, that claims reciting what it called "methods of calculation" other than specific mathematical formulas were held nonstatutory in In re Waldbaum, 559 F.2d 611, 194 USPQ 465 (CCPA1977) (computer-controlled method of computing the number of busy and idle lines in a telephone network), and In re Sarkar, 588 F.2d 1330, 200 USPQ 132 (CCPA1978) (methods of constructing and using a mathematical model of an open channel). Gelnovatch itself held to be nonstatutory an iterative method for automatically determining a set of process outputs which provide the calculated response most nearly equivalent to a goal response for a mathematical model of a microwave circuit. 595 F.2d at 35, 201 USPQ at 139. [FN2] Gelnovatch also offers the following guidance as to what constitutes a nonstatutory method of calculation:
Although the line separating statutory processes from nonstatutory processes is unclear, the mere presence of a calculation or the computer implementation of the method does not mandate a holding that the claimed procedure is not a "process" within the meaning of 35 USC 101. But, where, as here, the claims solely recite a method whereby a set of numbers is computed from a different set of numbers by merely performing a series of mathematical computations, the claims do not set forth a statutory process.
595 F.2d at 41-41, 201 USPQ at 145. Thus, it is apparent that the essence of a method of calculation in the § 101 sense, whether it is in the form of mathematical formula or equation or some other form, is the computation of one or more numbers from a different set of numbers by performing a series of mathematical computations. [FN3]
In view of the above, we believe a claim should be considered as reciting a mathematical algorithm only if it essentially recites, directly or indirectly, a method of computing one or more numbers from a different set of numbers by performing a series of mathematical computations. Consequently, a claim which essentially recites another type of method does not recite a mathematical algorithm, even though it incidentally requires, either directly or indirectly, the performance of some mathematical computations. [FN4] In our view, this approach correctly places the emphasis on what the claimed method steps do rather than how the steps are performed. [FN5]
*4 The examiner's position, on the other hand, appears to be that a claim must be considered as reciting a mathematical algorithm (i.e., method of calculation) if it directly or indirectly involves any mathematical relationships or calculations. Why we believe this position is much too broad is perhaps best illustrated by the following example. Consider an FM (frequency modulation) radio receiver implemented with analog (as opposed to digital) circuitry including, among other things, an analog mixer for frequency-converting a received FM radio frequency signal into an IF (intermediate frequency) signal, an analog detector for recovering audio frequency modulation signal from the IF signal and an analog amplifier for amplifying the audio frequency signal. Each of these components can be considered, and may in fact be described in the specification, as involving mathematical computations, such as addition, subtraction and multiplication. [FN6] Using the examiner's rationale, a method claim which recites the steps of frequency-converting, detecting and amplifying without expressly specifying any particular mathematical computations nevertheless would be considered to indirectly recite mathematical computations and thus a mathematical algorithm. The examiner has not identified, and we are unaware of, anything in the case law which supports such a conclusion.
Turning now to appellant's claims, in our opinion independent claims 1 and 14 (apparatus and method claims, respectively) do not recite a mathematical algorithm, because neither claim essentially recites, either directly or indirectly, a method of calculation, i.e., a method of computing one or more numbers from a different set of numbers by performing a series of mathematical computations. Considering method claim 14 in particular, while it is true that the claimed steps of establishing a baseline level, establishing a trigger level and generating inspiration trigger signals are disclosed as involving a series of mathematical computations, [FN7] the claim is not essentially directed to using these computations to compute one or more numbers from a different set of numbers. Instead, it is essentially directed to detecting the occurrence of events (i.e., commencement of inspiration intervals) by determining when a time-varying respiration signal crosses an adjustable trigger level. In addition, the claimed method accommodates abrupt DC shifts in the respiration signal by automatically detecting any shifts in the baseline value and re-establishing the baseline and trigger level values in response to any detected baseline shifts. Therefore, to the extent the disclosed computations are indirectly recited by the claim, we believe they are "merely ancillary to a more encompassing process[ ]." Gelnovatch, supra at 41, 201 USPQ at 145. This conclusion is perhaps more readily apparent if one assumes, merely for the sake of the above analysis, that the methods steps are implemented by analog circuitry rather than software. After all, as noted above, it is immaterial for purposes of determining nonstatutory subject matter whether the claimed method is implemented using hardware or software.
*5 For the foregoing reasons, neither method claim 14 nor "means plus function" apparatus claim 1 recites a mathematical algorithm. It is therefore unnecessary to consider whether these claims nevertheless pass muster under the second step of the Freeman-Walter test. Consequently, we will not sustain the § 101 rejection as to any of the appealed claims.
Turning now to the § 112, first paragraph, rejection (answer, p. 3), in spite of the examiner's references to the "written description requirement" and "best mode," it is clear from the statement of the rejection and the detailed discussion thereof that the sole basis for the rejection is the enablement requirement of § 112, first paragraph. In order to comply with this requirement the disclosure must be sufficiently full, clear, concise and exact to enable the artisan to practice the claimed invention without undue experimentation. In re Strahilevitz, 668 F.2d 1229, 1232, 212 USPQ 561, 563-64 (CCPA1982); In re Scarbrough, 500 F.2d 560, 182 USPQ 298 (CCPA1974); In re Brandstadter, 484 F.2d 1395, 179 USPQ 286 (CCPA1973). The examiner contends (answer, p. 3) that "[t]he specification fails to set forth how to make and use any hardware or structure and relies essentially on P-code to fulfil [sic] the written description [sic, enablement] requirement." [FN8] At the outset, we do not agree that the disclosure consists essentially of P-code. The disclosure also includes the block diagram of Fig. 1, whose operation is described in detail in the specification with the aid of the waveforms shown in Figs. 2-5. As will appear, we believe the disclosure as a whole provides adequate support for the subject matter specifically questioned by the examiner.
Specifically, the examiner contends (answer, p. 2) that "[t]he metaphors and relative terminology set forth in the specification and claims are inadequately defined and lack a best mode for enabling one to determine parameters for practicing the method." The "metaphors" of concern to the examiner (answer, p. 6) are the terms "thimble", "water" and "bucket," which were employed in the specification as filed (p. 6, line 28 to p. 7, line 2) to describe the operation of CVA detector 50 (Fig. 1). [FN9] More particularly, the specification states that when the heart rate and the respiration rate are within 12.5% of each other and a positive or negative trigger occurs within the CVA window, the CVA detector adds a "thimble of "water" to a "bucket." Each time a positive or negative trigger is generated outside the CVA window, two thimbles of water are removed from the bucket. The sizes of the thimble and bucket are selected such that if for ten seconds thimbles of water fill the bucket without any thimbles of water being removed from the bucket, the bucket overflows and the output of the inspiration detector will be inhibited. In our opinion, one skilled in the art would have had no difficulty understanding this metaphor or translating it into suitable software and/or hardware, such as an updown counter ("bucket") which is incremented one count ("thimble" of "water") at a time or decremented two counts at a time, with a predetermined count representing "overflow." Consequently, we believe the disclosure as filed is enabling with respect to the CVA detector, which is claimed as a means for and a step of "inhibiting generation of inspiration trigger signals" in dependent claims 9 and 22, respectively.
*6 The first of the "parameters" which the examiner considers inadequately disclosed is the trigger level 32, which is described (specification, p. 5, lines 1-6) as equal to the baseline value 30 plus a "predetermined minimum threshold level" minus a "threshold modifier." The "threshold modifier" is described as one-eighth of the difference between the positive peak boundary value and the negative peak boundary value (specification, p. 5, lines 7-10). [FN10] However, no specific value is disclosed for the "minimum threshold." Instead, the specification (p. 5, lines 10-20) states that if the patient is breathing normally (i.e., deeply), the operator sets the "minimum threshold" to be equal to a "predetermined threshold value" plus a "preset increased threshold value." On the other hand, if the patient's breathing is shallow, the operator sets the "minimum threshold" to be equal to the "shallow threshold" alone. No specific values are provided for either the "predetermined threshold value" or the "shallow threshold." However, the examiner has not demonstrated that the selection of these values would have been beyond the skill of the artisan. It is apparent from the discussion of the prior art in appellant's specification (p. 1, lines 9-20), which the examiner does not dispute, that it was already known prior to appellant's invention to employ a trigger level which is "a predetermined amount" above the baseline. The examiner has not explained, and it is not apparent to us, why an artisan familiar with this prior art would have had to engage in undue experimentation to select a "predetermined threshold value" and a "shallow threshold" suitable for use in the claimed invention.
The next "parameter" the examiner considers inadequately disclosed is the "fraction" or "positive boundary percentage" mentioned at page 7, line 20, of the specification, which is employed to derive the positive sector boundary 68 (Fig. 3) [FN11] from the baseline value 30 and the negative peak boundary 28 (page 7, lines 17-23). Similarly, a "fraction" or "negative boundary percentage" is employed to derive the negative sector boundary 70 (Fig. 3) [FN12] from the baseline value 30 and the positive peak boundary 26 (page 7, lines 23-31). The negative and positive sector boundaries "aid in resetting the baseline when there is a radical shift up or down in the dc level of the respiration waveform due to patient movement, for example" (specification, p. 8, lines 13-16). We agree with appellant (opening brief, p. 8) that the artisan would have recognized that the magnitudes of the above fractions or percentages determine the sensitivity of the detection of DC baseline shifts and thus can be selected to produce the desired degree of sensitivity. The examiner has not explained, and it is not apparent to us, why this selection process would have involved undue experimentation.
For the foregoing reasons, we also will not sustain the § 112, first paragraph (enablement requirement) rejection.
*7 In summary, we have not sustained the examiner's § 101 rejection or § 112, first paragraph (enablement requirement), rejection. Accordingly, the decision of the examiner is reversed.
James D. Thomas
Kenneth W. Hairston
John C. Martin
FN1. The examiner's answer (pp. 2-3) has identified a number of errors in claims 7, 14, 19 and 20 as reproduced in the appendix to appellant's brief.
FN2. See also In re Grams, 888 F.2d 835, 837, 12 USPQ2d 1824, 1826 (Fed.Cir.1989) (appellants therein conceded that the claimed steps of analyzing test data to ascertain the existence and identity of an abnormality constituted a mathematical algorithm), and Meyer, supra at 795, 215 USPQ at 198 (appellants therein conceded that the claimed process, which was designed to represent the analytical thought processes of a neurologist, recited a mathematical algorithm).
FN4. Only if a claim recites a mathematical algorithm in accordance with the above analysis is it necessary to determine whether the claim nevertheless passes muster under the second step of the Freeman-Walter test (as modified by Abele).
FN5. As noted earlier, the fact that a method step is performed by a programmed computer is immaterial.
FN6. As noted in In re Bernhart, 417 F.2d 1395, 1399-1400, 163 USPQ 611, 616 (CCPA1969), which is quoted in Chatfield, supra at 158, 191 USPQ at 735, "all machines function according to laws of physics which can be mathematically set forth if known." This is equally true of electrical and electronic circuits.
FN7. Referring to page 4, line 14 to page 6, line 4 of the specification, positive and negative peak boundaries 26 and 28 are exponentially related to the positive and negative peaks, respectively, of respiration signal 10; baseline level 30 at any given point in time equals one-half the difference between the values of the positive and negative peak boundaries; trigger level 32 equals the baseline level plus a predetermined minimum threshold value minus a threshold modifier; and the threshold trigger signals are generated when the respiration signal crosses (i.e., equals) the trigger level in a positive direction.
FN8. According to the November 11, 1988, declaration by appellant (paper No. 16), P-code is shorthand for "pseudo-code," which is defined in Random House Dictionary of the English Language (1987) as a "program code unrelated to the hardware of a particular computer and requiring conversion to the code used by the computer before the program can be used."
FN9. These terms were replaced by different terms in an amendment received October 13, 1987, which the examiner contends (answer, p. 2) introduced new matter into the specification. Since the question of whether new matter has been added to a specification is petitionable rather than appealable, we do not address it. The terms in question are not employed in the claims.
FN10. The examiner does not challenge the disclosure as to threshold modifier.
FN12. This boundary is labeled 68 in Fig. 2.