PTAB

IPR2015-00591

MaxLinear Inc v. Cresta Technology Corp

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Broadband Receiver Having a Multistandard Channel Filter
  • Brief Description: The ’585 patent describes a television receiver capable of processing multiple broadcast standards (e.g., analog and digital). The invention purports to solve issues of size and cost in prior art multi-standard receivers by replacing a bank of discrete, standard-specific analog filters with a single, programmable digital channel filter that processes an intermediate frequency (IF) signal in the digital domain.

3. Grounds for Unpatentability

Ground 1: Anticipation over Thomson - Claims 1, 2, 5, 16, 17, 18, and 19 are anticipated by Thomson under 35 U.S.C. §102.

  • Prior Art Relied Upon: Thomson (European Patent Application No. EP 0696854).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Thomson, filed in 1995, taught every element of the challenged claims. Thomson disclosed a multi-standard broadcast receiver for both analog and digital signals that converts a radio frequency (RF) signal to an IF signal. This IF signal is then filtered by an anti-aliasing filter, digitized by an analog-to-digital converter (ADC), and processed by an "adaptively controlled bandpass filter" (the claimed "signal processor"). The output of this digital filter is then fed in parallel to a plurality of demodulators (an FM demodulator for analog signals and a QPSK demodulator for digital signals) to generate baseband video and audio signals. Petitioner asserted that Thomson’s adaptive filter, which adjusts its bandwidth based on the incoming "TV standard," is a signal processor that performs the exact function recited in the claims.

Ground 2: Obviousness over Thomson in view of Harris - Claims 1, 2, 5, 10, and 16 are obvious over Thomson in view of Harris under 35 U.S.C. §103.

  • Prior Art Relied Upon: Thomson (European Patent Application No. EP 0696854) and Harris (a 1992 DSP Applications Magazine article).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground was presented as an alternative in case the "signal processor" of claim 1 is construed more narrowly to require the specific digital signal processor (DSP) structure described in the ’585 patent specification. While Thomson taught the overall architecture, it was silent on the specific implementation of its adaptive filter. Harris disclosed using a reconfigurable Finite Impulse Response (FIR) filter implemented on a DSP to replace a bank of filters, thereby saving cost and board space. Harris specifically taught a "512 TAP FIR" filter coupled to a "coefficient RAM" that could be reconfigured via a microprocessor interface, which Petitioner argued was structurally equivalent to the DSP described in the ’585 patent.
    • Motivation to Combine: A POSITA would combine Thomson with Harris to implement Thomson's adaptive filter using a well-known, cost-effective, and space-saving programmable DSP as taught by Harris. Harris explicitly suggested its reconfigurable filter for systems supporting "various operational modes," which directly applied to Thomson’s multi-standard (analog and digital) receiver.
    • Expectation of Success: The use of programmable FIR filters was a common design choice with well-understood and predictable results, ensuring a high expectation of success.

Ground 5: Obviousness over Thomson and Harris in further view of Balaban - Claims 13, 14, and 19 are obvious over Thomson and Harris in further view of Balaban.

  • Prior Art Relied Upon: Thomson (European Patent Application No. EP 0696854), Harris (a 1992 DSP Applications Magazine article), and Balaban (Patent 6,369,857).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground targeted claims requiring a "standard selection circuit" that generates a select signal to control the signal processor. Thomson disclosed that its adaptive filter was controlled by a "Television Standard" input signal but did not detail the circuit that generated it. Balaban addressed the same problem as the ’585 patent—a generic receiver for different TV standards—and explicitly taught a circuit that automatically selects whether a received signal is in analog or digital format by detecting the presence or absence of carrier signals. Claim 14’s limitation of a user-selectable input was also taught by Balaban, which disclosed providing a "user-selectable default condition" via a switch or programming feature.
    • Motivation to Combine: A POSITA implementing the Thomson/Harris receiver would need a way to generate the "Television Standard" control signal. A POSITA would naturally look to references like Balaban, which solved the identical problem of automatic standard selection, to provide the implementation details for this control circuit.
    • Expectation of Success: Combining Balaban's known selection circuit with the Thomson/Harris receiver architecture was a straightforward integration of known components to achieve a predictable function.

  • Additional Grounds: Petitioner asserted additional obviousness challenges, including combining Thomson with Admitted Prior Art from the ’585 patent to ensure disclosure of baseband audio/video outputs (Ground 3), and combining Thomson with Kerth (Patent 6,804,497) to teach adding a digital-to-analog converter (DAC) before an analog demodulator (Ground 4).

4. Key Claim Construction Positions

  • "signal processor": Petitioner contended that the broadest reasonable construction for this term, as used in claims 1-16, is a "digital module that processes signals in the digital domain." Petitioner argued this construction was supported by the specification’s description of a "digital signal processor DSP 64" and contemporaneous prior art. This construction is central to Ground 1 (anticipation), while the alternative obviousness ground (Ground 2) was presented in the event the term was construed more narrowly to require the specific DSP structure disclosed in the specification.

5. Arguments Regarding Discretionary Denial

  • Petitioner noted that a separate IPR on the ’585 patent, IPR2014-00728 filed by a different party (Silicon Laboratories), had already been instituted on many of the same claims. Petitioner requested that the Board institute this petition but hold the grounds in abeyance pending the outcome of the earlier IPR. This request was made to preserve Petitioner's right to challenge the claims in the event the earlier IPR was terminated due to settlement before a final decision.

6. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1–3, 5, 10, 13, 14, and 16–19 of the ’585 patent as unpatentable.