Rohde Schwarz GmbH Co KG v. Tektronix Inc

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: ROHDE & SCHWARZ GMBH & CO. KG (Germany)
  • Defendant: Tektronix, Inc. (Oregon)
  • Plaintiff’s Counsel: FISH & RICHARDSON P.C.
• Case Identification: 2:18-cv-02402, C.D. Cal., 03/23/2018
• Venue Allegations: Venue is alleged to be proper based on Defendant operating a regular and established place of business in the district, specifically a calibration and service facility in Covina, California, and by conducting sales and service activities related to the accused products within the district.
• Core Dispute: Plaintiff alleges that Defendant’s Digital Phosphor Oscilloscopes and Mixed Signal Oscilloscopes infringe a patent related to methods for improving the accuracy of digital triggering in oscilloscopes.
• Technical Context: The technology at issue addresses precision triggering for digital oscilloscopes, a critical function for capturing and analyzing high-speed or complex electronic signals in research, development, and debugging.
• Key Procedural History: The complaint does not mention any prior litigation, inter partes review (IPR) proceedings, or licensing history related to the patent-in-suit. The complaint alleges Defendant had notice of the patent, at the latest, upon the filing of this lawsuit, which may be relevant to the timing of any potential willfulness finding.

Case Timeline

Date	Event
2005-07-27	U.S. Patent No. 7,860,674 Priority Date
2010-12-28	U.S. Patent No. 7,860,674 Issue Date
2018-03-23	Complaint Filing Date

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 7,860,674 - Method and System for Secure Digital Triggering for an Oscilloscope, Issued December 28, 2010

The Invention Explained

• Problem Addressed: The patent's background describes a problem inherent in digital oscilloscopes where a signal is measured at discrete time intervals (sampling). If a triggering event (e.g., a signal crossing a voltage threshold) occurs between two sample points, the oscilloscope's display can be imprecise, a phenomenon known as "jitter." (’674 Patent, col. 1:48-61). Furthermore, a signal event, such as a peak that occurs entirely between two samples, might be missed altogether, preventing a trigger from occurring when it should. (’674 Patent, col. 2:10-13).
• The Patented Solution: The invention proposes a digital triggering method that improves time resolution beyond the limits of the physical sampling rate. Instead of relying only on actual measured samples, the system calculates "at least one additional sampled value" between two successive real samples using "interpolation." (’674 Patent, Abstract). By creating these new, interpolated data points, the system can more accurately determine the precise moment a signal crosses a threshold, thereby reducing jitter and ensuring that trigger events occurring between samples are not missed. (’674 Patent, col. 2:36-55).
• Technical Importance: This digital interpolation technique allows an oscilloscope to achieve a higher effective time resolution for triggering than its analog-to-digital converter's hardware sampling rate would otherwise permit. (’674 Patent, col. 2:29-34).

Key Claims at a Glance

• The complaint asserts independent claims 1 (a method) and 18 (a system) (Compl. ¶20).
• Independent Claim 1 includes the key elements of:
  • Implementing a level comparison to determine a triggering time between two successive sampled values and a threshold value.
  • Determining at least one "additional sampled value" between the successive sampled values.
  • The additional value is calculated by "interpolation" if the threshold value is "disposed either above both of or below both of" the successive sampled values.
  • Using the additional sampled value to determine the triggering time.
• Independent Claim 18 recites a system with corresponding components:
  • A "comparator" for performing the level comparison.
  • A "unit" configured to determine additional sampled values by interpolation.
  • The unit performs a "calculation of second additional sampled values" if the threshold is identified as being above or below both successive samples.
  • The additional values are used to determine a triggering time.
• The complaint reserves the right to assert dependent claims 5, 14, 19, 20, 22, and 23. (Compl. ¶20).

III. The Accused Instrumentality

Product Identification

• The accused instrumentalities are Defendant’s Digital Phosphor Oscilloscope (DPO) and Mixed Signal Oscilloscope (MSO) products, and associated software. (Compl. ¶¶18, 21). The "5 Series MSO" is specifically identified as an infringing product line. (Compl. ¶22).

Functionality and Market Context

• The accused products are test and measurement instruments used for debugging and verifying electronic components. (Compl. ¶15). The complaint alleges that these oscilloscopes incorporate a "digital trigger" functionality. (Compl. ¶22). It further alleges, based on Defendant's promotional materials, that these products include "advanced trigger capabilities with integrated digital trigger support" and "some more power DSP features enabled," which provide users with "new levels of adjustment and confidence." (Compl. ¶22).

IV. Analysis of Infringement Allegations

No probative visual evidence provided in complaint. The complaint references an exemplary claim chart in Exhibit 3, which was not included with the filed complaint document. The narrative infringement theory is summarized below.

The complaint alleges that Tektronix's DPO and MSO products directly infringe the ’674 Patent because their "digital trigger" functionality performs the patented method. (Compl. ¶¶ 20-21). The core of the infringement theory is that the "advanced trigger capabilities" provided by the accused oscilloscopes achieve higher precision by implementing the patented steps of calculating additional data points between actual hardware samples via interpolation. (Compl. ¶22). The complaint cites Tektronix's own marketing and technical documents, which allegedly describe the use of Digital Signal Processing (DSP) to enable these advanced trigger features, as evidence that the accused products practice the claimed invention. (Compl. ¶22).

• Identified Points of Contention:
  • Technical Question: A primary factual dispute may center on the precise operation of the accused "digital trigger." The key question is whether the DSP-based features in Tektronix's products actually "calculate" an "additional sampled value" using "interpolation" as required by the claims, or if they employ a different, non-infringing technical method to enhance trigger stability and precision.
  • Scope Question: Claim 1 requires interpolation to be performed specifically "if the threshold value is disposed either above both of or below both of the two successive sampled values." This describes a situation where a trigger event might be missed entirely. The infringement analysis raises the question of whether the accused products' trigger logic includes this specific condition, or if their trigger enhancement is a more general process that does not align with this explicit claim limitation.

V. Key Claim Terms for Construction

• The Term: "additional sampled value ... calculated by interpolation"
  • Context and Importance: This phrase captures the core inventive concept. The outcome of the case may depend on whether the function performed by the accused devices' DSP is properly characterized as calculating an "additional sampled value" via "interpolation." Practitioners may focus on this term because Defendant could argue that its real-time signal processing does not create a new, discrete "value" or that its technique is not "interpolation" as described in the patent.
  • Intrinsic Evidence for a Broader Interpretation: The specification introduces interpolation as a general concept to achieve higher time resolution and does not explicitly limit the term to a single algorithm, noting that the interpolator is "preferably a polyphase filter." (’674 Patent, col. 6:44-45).
  • Intrinsic Evidence for a Narrower Interpretation: The patent provides detailed descriptions and figures illustrating specific iterative methods, such as the bisection method shown in the flowchart of Fig. 8B, for calculating the interpolated values. (’674 Patent, col. 6:51-67; Fig. 8B). A party could argue the term should be construed in light of these specific, disclosed embodiments.
• The Term: "if the threshold value is disposed either above both of or below both of the two successive sampled values"
  • Context and Importance: This limitation defines the specific logical condition under which the claimed interpolation must occur. Infringement requires not just interpolation, but interpolation performed in response to this particular state—where a signal may have crossed a threshold and returned between two samples. The construction of this term is critical because it distinguishes the invention from a system that might use interpolation for every trigger.
  • Intrinsic Evidence for a Broader Interpretation: A plaintiff would likely argue that the language is plain and its meaning is clear, covering any system that detects this condition and uses interpolation to find a potential missed trigger between the samples.
  • Intrinsic Evidence for a Narrower Interpretation: The patent’s flowcharts, such as Fig. 10A, depict this check as a discrete, explicit step (S710) that precedes the interpolation step (S720). A defendant could argue that this claim language requires a specific, sequential logic that may not be present in its integrated DSP-based trigger system. (’674 Patent, Fig. 10A).

VI. Other Allegations

• Indirect Infringement: The complaint alleges both induced and contributory infringement. The inducement allegation is based on Tektronix allegedly encouraging infringement by end-users through marketing materials, product literature, datasheets, manuals, and technical support that instruct on using the infringing "digital trigger" features. (Compl. ¶22). The contributory infringement allegation is based on the sale of the accused oscilloscopes, which are alleged to be a material part of the invention, especially made for infringement, and not a staple article of commerce. (Compl. ¶23).
• Willful Infringement: The complaint alleges that Tektronix's infringement is willful and seeks a finding that the case is "exceptional." (Compl. p. 9, ¶(c)). However, the factual basis for willfulness is asserted to arise "at least upon the filing or service of this Complaint," suggesting the allegation is primarily directed at post-filing conduct. (Compl. ¶22).

VII. Analyst’s Conclusion: Key Questions for the Case

• A key evidentiary question will be one of technical implementation: does the accused "digital trigger" functionality in Tektronix's oscilloscopes operate by "calculating an additional sampled value... by interpolation" as understood in the context of the ’674 patent, or does it rely on a different, non-infringing signal processing technique to achieve trigger precision?
• A central legal and factual question will be one of conditional operation: can the plaintiff demonstrate that the accused products perform this interpolation specifically in response to the condition where a "threshold value is disposed either above both of or below both of the two successive sampled values," as explicitly required by the claims, or is that specific logic absent?