Broadband frequency translation for high frequency regeneration
First Claim
1. A method performed by a device for generating a reconstructed signal that comprises:
- the device receiving a signal containing data representing a baseband signal derived from an audio signal and an estimated spectral envelope;
the device obtaining from the data a frequency-domain representation of the baseband signal, the frequency-domain representation comprising baseband spectral components;
the device obtaining a regenerated signal comprising regenerated spectral components by copying into individual subbands the lowest-frequency baseband spectral components to a lower edge of a respective subband and continuing through the baseband spectral components in a circular manner to complete a translation for that respective subband; and
the device obtaining a time-domain representation of the reconstructed signal corresponding to a combination of the baseband spectral components, the regenerated spectral components and the estimated spectral envelope.
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Abstract
An audio signal is conveyed more efficiently by transmitting or recording a baseband of the signal with an estimated spectral envelope and a noise-blending parameter derived from a measure of the signal'"'"'s noise-like quality. The signal is reconstructed by translating spectral components of the baseband signal to frequencies outside the baseband, adjusting phase of the regenerated components to maintain phase coherency, adjusting spectral shape according to the estimated spectral envelope, and adding noise according to the noise-blending parameter. Preferably, the transmitted or recorded signal also includes an estimated temporal envelope that is used to adjust the temporal shape of the reconstructed signal.
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Citations
15 Claims
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1. A method performed by a device for generating a reconstructed signal that comprises:
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the device receiving a signal containing data representing a baseband signal derived from an audio signal and an estimated spectral envelope; the device obtaining from the data a frequency-domain representation of the baseband signal, the frequency-domain representation comprising baseband spectral components; the device obtaining a regenerated signal comprising regenerated spectral components by copying into individual subbands the lowest-frequency baseband spectral components to a lower edge of a respective subband and continuing through the baseband spectral components in a circular manner to complete a translation for that respective subband; and the device obtaining a time-domain representation of the reconstructed signal corresponding to a combination of the baseband spectral components, the regenerated spectral components and the estimated spectral envelope. - View Dependent Claims (2, 3, 4, 5)
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6. An apparatus for generating a reconstructed signal that comprises:
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means for receiving a signal containing data representing a baseband signal derived from an audio signal and an estimated spectral envelope; means for obtaining from the data a frequency-domain representation of the baseband signal, the frequency-domain representation comprising baseband spectral components; means for obtaining a regenerated signal comprising regenerated spectral components by copying into individual subbands the lowest-frequency baseband spectral components to a lower edge of a respective subband and continuing through the baseband spectral components in a circular manner to complete a translation for that respective subband; and means for obtaining a time-domain representation of the reconstructed signal corresponding to a combination of the baseband spectral components, the regenerated spectral components and the estimated spectral envelope. - View Dependent Claims (7, 8, 9, 10)
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11. A non-transitory storage medium that is readable by a device and that records a program of instructions executable by the device to perform a method for generating a reconstructed signal, wherein the method comprises:
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receiving a signal containing data representing a baseband signal derived from an audio signal and an estimated spectral envelope; obtaining from the data a frequency-domain representation of the baseband signal, the frequency-domain representation comprising baseband spectral components; obtaining a regenerated signal comprising regenerated spectral components by copying into individual subbands the lowest-frequency baseband spectral components to a lower edge of a respective subband and continuing through the baseband spectral components in a circular manner to complete a translation for that respective subband; and obtaining a time-domain representation of the reconstructed signal corresponding to a combination of the baseband spectral components, the regenerated spectral components and the estimated spectral envelope. - View Dependent Claims (12, 13, 14, 15)
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Specification