Apple Inc. v. Andrea Elecs. Corp.

• Citation: 949 F.3d 697
• Decision Date: 07 February 2020
• Docket Number: 2018-2382, 2018-2383
• Parties: APPLE INC., Appellant v. ANDREA ELECTRONICS CORPORATION, Appellee
• Court: United States Courts of Appeals. United States Court of Appeals for the Federal Circuit

949 F.3d 697

APPLE INC., Appellant

v.ANDREA ELECTRONICS CORPORATION, Appellee

2018-2382, 2018-2383

United States Court of Appeals, Federal Circuit.

Decided: February 7, 2020

Jeffrey Paul Kushan, Sidley Austin LLP, Washington, DC, argued for appellant. Also represented by Thomas Anthony Broughan, III, Christin Sullivan Miller.

William D. Belanger, Pepper Hamilton LLP, Boston, MA, argued for appellee. Also represented by Bradley Thomas Lennie, Goutam Patnaik, Washington, DC.

Before Dyk, Plager, and Stoll, Circuit Judges.

Plager, Circuit Judge.

The patent at issue in this appeal, U.S. Patent No. 6,363,345 ("the ’345 patent"), relates to certain aspects of digital audio processing. On September 19, 2016, Andrea Electronics Corp. ("Andrea or Appellee"), assignee of the ’345 patent, sued Apple, Inc. ("Apple or Appellant") for infringement of the ’345 patent in the Eastern District of New York. J.A. 1151–70. On January 9, 2017, Appellant Apple filed two inter partes review ("IPR") petitions—the ’626 IPR and ’627 IPR—with the U.S. Patent and Trademark Office, challenging the validity of claims 1–25 and 38–47 of the patent.

The Patent Trial and Appeal Board ("Board") instituted review of both petitions and consolidated the proceedings. In its ’626 IPR Final Written Decision, the Board concluded that, in light of the prior art cited by Apple, all challenged claims except claims 4–11 and 39–47 of the ’345 patent are unpatentable. In the course of reaching that conclusion, the Board declined to consider certain arguments in Apple’s ’626 IPR reply brief applicable to claims 6–9 on the ground that Apple was raising new arguments in its reply brief that were not entitled to consideration at that late stage in the proceedings.

In its ’627 IPR Final Written Decision, the Board concluded that, in light of other cited art, all challenged claims of the ’345 patent except claims 6–9, 17–20, 24, and 47 are unpatentable. In reaching that conclusion, the Board adopted a claim construction of the claim term "periodically" in favor of Andrea that supported its analysis. Between the two IPRs, the Board held that all challenged claims except claims 6–9 are unpatentable.

With regard to the ’626 IPR Board decision, Apple appeals the Board’s conclusion that claims 6–9 are surviving claims, arguing that had the Board properly considered its reply brief arguments, that would not have been the outcome. With regard to the ’627 IPR Board decision, Apple argues that the Board erred in its conclusion that, based on the prior art cited, claims 6–9 are not unpatentable as either anticipated or obvious.

With respect to the ’626 IPR, for the reasons we shall explain, we conclude that the Board erred in refusing to consider Apple’s reply arguments. Accordingly, we vacate the Board’s decision in the ’626 IPR, and remand for reconsideration of Apple’s reply brief arguments addressing the indicated prior art reference.

With respect to the ’627 IPR, we find that the Board’s decision with regard to the validity of the patent claims in its ’627 IPR Final Written Decision was correctly reached. We therefore affirm the Board with respect to the ’627 IPR.

I. BACKGROUND

A. Digital Audio Processing

Because an understanding of the issues and our disposition of them require some familiarity with the technology of sound and digital audio processing, we begin with that. Sound is the physical vibrations of a medium, such as air. These vibrations are often depicted in the form of a sinusoidal wave, a "sine wave," with time on the x-axis (horizontal), and the amplitude of the signal (roughly, volume) on the y-axis (vertical).

J.A. 833.

In addition to the amplitude, the frequency (cycles per period of time) of a sound wave is a particularly relevant factor for human hearing. While amplitude roughly corresponds to volume, frequency corresponds to the pitch of the sound.

Music and speech are generally comprised of sound at different frequencies (e.g., a musical chord consists of several notes played simultaneously). When multiple notes are played at the same time, the graphical representation of the resulting signal may look different from a simple sine wave:

J.A. 836. The resulting graph is a composite of several different sine waves, each corresponding to an individual frequency and amplitude. To determine which frequencies make up the signal, the signal can be converted to the frequency domain via a well-known mathematical formula called a "Fourier transform."

Digital signal processing frequently uses Fourier transforms to convert sounds between the time domain and frequency domain because it is computationally easier to make certain modifications to the signal in the frequency domain than in the time domain. This conversion to the frequency domain results in a histogram, in which the signal is divided into "frequency bins" and each bin corresponds to one of the frequencies present in the signal. The magnitude of a particular frequency is represented on the y-axis.

B. The ’345 Patent

The patent at issue, the ’345 patent, describes a method, system, and apparatus that utilizes Fourier transforms and a process known as "spectral subtraction" for noise cancellation and reduction purposes. The disclosed system converts an audio signal to the frequency domain via Fourier transforms, sets separate thresholds for each "frequency bin" in order to distinguish the background noise, and then employs "spectral subtraction" to remove ambient noise without affecting speech and its characteristics. ’345 patent, col. 6 ll. 10–13.

In order to determine the appropriate threshold for each frequency bin, the system sets two minimum values, which are described as a "future minimum" and a "current minimum." ’345 patent, col. 6 ll. 23–41. At predetermined time intervals (e.g., every five seconds), the future minimum value is initialized as the value of the current magnitude of the signal. ’345 patent, col. 6 ll. 24–28. Over that time interval, the future minimum is compared with the current magnitude value of the signal. If the observed magnitude is less than the value of the future minimum, then the future minimum is set equal to that newly observed lower value. ’345 patent, col. 6 ll. 24–32.

At the start of each time interval, the current minimum is set as the value of the future minimum that was determined over the previous time interval. ’345 patent, col. 6 ll. 34–38. The current minimum value then follows the minimum value of the signal over the next time interval by comparing its value with the current magnitude value. ’345 patent, col. 6 ll. 34–38. The final current minimum value is used to calculate the adaptive threshold.

This adaptive threshold is used in a process known as "spectral subtraction," in which the value of the estimated "noise magnitude" is subtracted from the current magnitude value of the bin. The result is a cleaner signal with some of the noise removed.

C. The Claims at Issue

Claims 6–9 of the ’345 patent are the only claims at issue in this appeal. Claims 6–9 depend from claim 5, which depends from claim 4, which depends from claim 1:

1. An apparatus for cancelling noise, comprising:

An input for inputting an audio signal which includes a noise signal;

A frequency spectrum generator for generating the frequency spectrum of said audio signal thereby generating frequency bins of said audio signal; and

A threshold detector for setting a threshold for each frequency bin using a noise estimation process and for detecting for each frequency bin whether the magnitude of the frequency bin is less than the corresponding threshold, thereby detecting the position of noise elements for each frequency bin.

’345 patent, col. 9 ll. 34–46 (emphasis added).

Claim 4 adds features to the threshold detector, noting that the threshold detector "sets the threshold for each frequency bin in accordance with a current minimum value of the magnitude of the corresponding frequency bin; said current minimum value being derived in accordance with a future minimum value of the magnitude of the corresponding frequency bin." ’345 patent, col. 9 ll. 54–60.

Claim 5 adds that the "future minimum value is determined as the minimum value of the magnitude of the corresponding frequency bin within a predetermined period of time." Thus claims 6–9 depend ultimately from claim 5, and place specific limits on how the "current minimum value" or "future minimum value" are determined.

Claim 6 recites:

The apparatus according to claim 5, wherein said current minimum value is set to said future minimum value periodically.

’345 patent, col. 9, ll. 65–67.

Claim 7 recites:

The apparatus according to claim 6, wherein said future minimum value is replaced with the current magnitude value when said future minimum value is greater than said current magnitude value.

’345 patent, col. 10, ll. 1–4.

Claim 8 recites:

The apparatus according to claim 6, wherein said current minimum value is replaced with the current magnitude value when said current minimum value is greater than said current magnitude value.

’345 patent, col. 10, ll. 5–8.

Claim 9 recites:

The apparatus according to claim 5, wherein said future minimum value is set to a current magnitude value periodically; said current-magnitude value being the value of the magnitude of the corresponding frequency bin.

’345 patent, col. 10, ll. 9–12.

II. The Issues

A. The ’626 and ’627 IPR Proceedings

As noted, Apple filed its two IPR petitions—the ’626 IPR and the ’627 IPR—challenging claims 1–25 and 38–47 of the ’345 patent. Relevant to this appeal, Apple alleged that the challenged claims would have been anticipated or obvious in light of three pieces of prior art.

In its ’626 IPR petition, Apple alleged that claims 6–9 of the ’345 patent would have been obvious over Hirsch and Martin. Apple alleged in its ’627 IPR petition that claims 6–9 are anticipated by Helf or would have been obvious over Helf and Martin. The Board instituted review on all challenged claims and grounds raised in both petitions and...