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High frequency replication utilizing wave and noise information in encoding and decoding audio signals

  • US 10,643,630 B2
  • Filed: 07/30/2019
  • Issued: 05/05/2020
  • Est. Priority Date: 01/14/2011
  • Status: Active Grant
First Claim
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1. A signal processing device comprising:

  • an extracting unit that extracts a low frequency component of an audio signal, envelope information representing an envelope of a high frequency component of the audio signal, noise envelope information representing a noise boundary position for dividing a noise signal included in the high frequency component into zones and a noise signal gain for each of the zones, and sine wave information which includes information representing a distance from a start position of a frame of the high frequency component to an appearance start position of a sine wave component included in the high frequency component, and is for specifying a frequency and an appearance position of the sine wave component, wherein the start position for the sine wave component is independent of the noise boundary position;

    a pseudo high frequency generating unit that generates a pseudo high frequency signal configuring the high frequency component on the basis of a low frequency signal as the low frequency component and the envelope information;

    a sine wave generating unit that generates a sine wave signal which is at a frequency represented by the sine wave information and in which the appearance start position specified from the sine wave information is set as a start position;

    a noise generating unit configured to generate a noise signal configuring the high frequency component by adjusting, for a predetermined signal having zones divided by the noise boundary position, a gain for each zone of the predetermined signal on the basis of the noise signal gain represented by the noise envelope information; and

    a combining unit that combines the low frequency signal, the pseudo high frequency signal the sine wave signal, and the noise signal to generate an audio signal.

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