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US 8,027,480 B2Granted
Multichannel spectral mapping audio apparatus and method
AssigneeTerry D. Beard
InventorTerry D. Beard
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Abstract
A method and circuit for deriving a set of multichannel audio signals from a conventional monaural or stereo audio signal uses an auxiliary multichannel spectral mapping data stream. Audio can be played back in stereo and multichannel formats from a conventional stereo signal on compact discs, FM radio, or other stereo or monaural delivery systems. The invention reduces the data rate needed for the transmission of multichannel digital audio.
Claims7
An audio medium playback system, comprising:
- a receiver for receiving an audio signal with a set of spectral mapping coefficients, and the audio signal is transmitted on a digital medium;
- a digital signal processor implemented on an integrated circuit (IC) chip, and the digital signal processor configured for performing operations for reproducing on a target signal the audio signal present on a source signal, the operations comprising:
- receiving the audio signal organized into successive temporal aperture periods, including a phase component, in digital format on the source signal along with a set of spectral mapping coefficients for each of said aperture periods that vary among said aperture periods, and that, for each band of the source signal, map a signal level within that band onto desired signal levels for corresponding bands of the target signal, where the spectral mapping coefficients are defined by an encoding process that is independent of an audio signal decoding process;
- and
- applying the spectral mapping coefficients to the audio signal present on the source signal to obtain the audio signal on the target signal;
- a digital-to-analog (D/A) converter for converting the target signal into a multichannel analog audio output signal;
- an equalizer for equalizing the multichannel analog audio output signal;
- and
- a speaker for outputting the multichannel analog audio output signal.
6 more elements
Dependencies are inferred from the claim text.