examiner did not ask that the claims be amended to include these descriptions and the patent was subsequently allowed. Accordingly, for the same reasons given above with respect to the sequencer element, the court will not import limitations found in the preferred embodiment into an otherwise understandable claim. The mode select output is for selecting one of a plurality of data patterns and the step select output is for selecting one of a plurality of time segments in response to that pattern.
3. Plurality of Predetermined Waveforms
Again, Seeq proposes augmenting the definition of "a plurality of predetermined waveforms" with a description taken directly from the preferred embodiment, specifically from column 4, lines 8-18, and adding to it that the "six predetermined waveforms are illustrated in Figures 7A and 7B of the '269 Patent (where the seventh pattern, "idle," is zero)." Level One objects that what is stored in memory is data that "represents" a plurality of predetermined waveforms and how the data represents the waveforms may vary. Therefore, the term cannot be limited to the example shown in Figure 7B which happens to show the data patterns in seven time segments as four-bit data words.
Level One is correct that the predetermined waveforms are "representative" rather than actual. The specification repeatedly refers to them as such. '269 Patent at Abstract, 4:8-16. The specification also specifically notes that the applicants found that a value of N equal to seven provided sufficient temporal resolution, '269 Patent at 4:25-28, but suggests that other values could readily be substituted.
Apart from the dispute over whether the predetermined waveforms are representative or as depicted in Figures 7A and 7B, it is not clear that the parties disagree. The section of the preferred embodiment cited by Seeq consistently refers to the predetermined waveforms as "representative of a desirous output response by a hypothetical transmit filter when excited with predistorted Manchester encoded data." '269 Patent at 4:9-11. While Level One appears to have no objection to this description and it is useful to understanding the term at issue, the court is not inclined to import it into the definition of "a plurality of predetermined waveforms." The court rejects defendant's theory of claim construction, which would incorporate any description of a given claim term in the specification into the claim itself. As the court has already noted in this order, it is not the purpose of a Markman hearing to seek to strategically limit a patent's claims under the guise of a genuine dispute as to meaning. While claims are read in light of the specification, "it does not follow that limitations from the specification may be read into the claims . . . ." Sjolund v. Musland, 847 F.2d 1573, 1581 (Fed. Cir. 1988); accord E.I. Du Pont de Nemours & Co. v. Phillips Petroleum Co., 849 F.2d 1430, 1433 (Fed. Cir. 1988) ("It is entirely proper to use the specification to interpret what the patentee meant by a word or a phrase in the claim. But this is not to be confused with adding an extraneous limitation appearing in the specification, which is improper.") (citations omitted); see also Ekchian v. Home Depot, Inc., 104 F.3d 1299, 1303 (Fed. Cir. 1997).
Both parties seem to understand that predetermined waveforms are simply representative waveforms set in advance to compensate for known transmission distortion. Therefore, the court adopts that construction.
It appears that the parties no longer substantively disagree on the meaning of multiplexer and therefore the court construes it as they do, as "having inputs coupled to the step select output, mode select output, and the memory, and an output bus for providing channeled data from the memory, representing a selected waveform in response to the step and mode select outputs."
5. Differential Input and Transmission Line
The last element of Claim 1 reads "driver means including low pass filter means having a differential input coupled to the current output for impressing an analog voltage onto a transmission line." '269 Patent at 7:1-4. With respect to the differential output, the parties' now appear to agree that the term refers to the driver means and not the low pass filter means, thus the court accepts that construction.
The parties do dispute what transmission line includes. Seeq contends that it should be interpreted to include "any alternative transmission media which exhibit lossy characteristics, including twisted pair wire or radio frequency." Level One asserts that a transmission line refers to communication over a physical connection such as a line, a wire or a cable and that ether is not a lossy media. The court agrees that even though distortion may occur with radio transmission, the term transmission line suggests a physical media and it does not logically apply to radio frequency. While the '269 patent states that it "relates generally to problems in data communication systems having a lossy transmission media," '269 Patent at 1:7-9, it more specifically addresses "conventional transmission lines, such as twisted-pair cable" later in the specification. '269 Patent at 1:29-30. Accordingly, the court construes transmission line to encompass lossy physical media, such as lines, wire and cable.
B. Claim 8
The principal dispute over Claim 8 is whether or not it should be read as a mean-plus-function claim. Claim 8 reads:
A method for transmit equalization comprising the steps of: a) receiving input data in a non-return to zero format and providing multiplexer control signals in response thereto; b) storing output data representing a plurality of predetermined waveforms; c) multiplexing the output data representing one of the predetermined waveforms into a bus; d) de-skewing the output data on the bus; e) converting the output data on the bus into a differential analog signal; and f) impressing the analog signal onto a transmission line.
'296 Patent at 8:8-21.
Seeq argues that it should be read as a mean-plus-function claim because the claim is drafted as a series of steps for performing a function, i.e. transmit equalization, without recital of their corresponding structures. Seeq further requests the court to identify the structures for "providing multiplexer control signals," "multiplexing" and "de-skewing."
Level One argues that despite the word "steps" in the claim preamble, Claim 8 is a method claim written as a procession of functions that must be interpreted to cover all means for performing the functions recited in the claim. Plaintiff, citing Greenberg v. Ethicon Endo-Surgery, Inc., 91 F.3d 1580 (Fed. Cir. 1996), contends that the "step" language is not determinative of whether section 112(6) applies. Plaintiff also points to the fact that the Patent Office did not read Claim 8 as a means-plus-function claim and argues that this is relevant because the Federal Circuit has concluded that section 112(6) applies equally to prosecution and litigation. In re Alappat, 33 F.3d 1526, 1540 (Fed. Cir. 1994).
The Federal Circuit has recently addressed the considerations relevant to applying section 112(6). In Cole v. Kimberly-Clark Corp., 102 F.3d 524, 530-31 (Fed. Cir. 1996), the court noted that traditional "means" language does not automatically make an element a means-plus-function element and that conversely, lack of such language does not prevent an element from being construed as a means-plus-function element. Id. at 531. Instead, a court must decide on an "element-by-element basis" based upon the patent and the prosecution history whether section 112(6) applies. Id. In order to invoke section 112(6), "the alleged means-plus-function claim element must not recite a definite structure which performs the described function." Id. In Cole, the court affirmed a district court's conclusion that "perforation means . . . for tearing" was not a means-plus-function element under section 112(6) because despite the fact that the drafter of the patent "was clearly enamored of the word 'means'" the claim described the structure that performed the tearing function, namely the perforation. Id. at 530-31.
In Greenberg, the Federal Circuit noted that it is generally clear when drafters intend to invoke section 112(6) by their use of the standard language "means for" or "step for". 91 F.3d at 1583. In that case the claim involved a "detent mechanism defining the conjoint rotation of said shafts" which was not in conventional means-plus-function language. In reversing the district court's conclusion that it was a means-plus-function element, the court stated that "the fact that a particular mechanism--here 'detent mechanism'--is defined in functional terms is not sufficient to convert a claim element containing that term into a 'means for performing a specified function' within the meaning of section 112(6)." Id.
Claim 8 is not written as a means-plus-function claim, nor does the word "steps" in the preamble make it so; such a reading would make every process claim into a means-plus-function claim by definition. Rather, it is written as a standard process or method claim. See, e.g., Environmental Designs Ltd. v. Union Oil Co. of California, 713 F.2d 693, 694 (Fed. Cir. 1983). Whether it should also be read as a means-plus-function claim depends on whether it adequately recites the structures for the functions it describes. Contrary to Level One's contention, whether the patent examiner analyzed the claim under section 112(6) is not determinative, particularly since the '269 patent issued before the Federal Circuit conclusively held that application of section 112(6) was part of the patent determination made by the PTO. In re Donaldson, 16 F.3d at 1193-95.
Reviewing Claim 8 on an element-by-element basis, the court concludes that Claim 8 is not a means-plus-function claim. Each of the functions recited as part of the claimed method have a corresponding structure that is evident from the language of Claim 8 itself or from Claim 1. First, it is clear from the patent and Claim 1 that the sequencer "provides multiplexer control signals" in the form of mode select and step select outputs.
'269 Patent at 6:51-53. Second, "multiplexing" clearly corresponds to the multiplexer construed above. See Greenberg, 91 F.3d at 1583 ("Many devices take their name from the functions they perform."). Lastly, Claim 1 makes it evident that the latch performs the "de-skewing" function. '269 Patent at 6:62-64 ("a latch having an input coupled to the output bus and an output for de-skewing the data representing the select waveform").
For the aforementioned reasons, the court construes the disputed terms of the '183 Patent and the '269 Patent as set forth above.
IT IS SO ORDERED.
Date: Nov 10, 1997
MARILYN HALL PATEL
United States District Judge
Northern District of California