US5727119A
Expired / Lapsed
US
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Method and apparatus for efficient implementation of single-sideband filter banks providing accurate measures of spectral magnitude and phase
Assignee: Dolby Laboratories Licensing Corp
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Filing: 1995-03-27
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Granted: 1998-03-10
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Expires: 2015-03-27
Abstract
Abstract Accurate measures of estimated spectral power and phase are derived from two spectral representations of each of one or more input signals generated by single-sideband filter banks including critically-sampled perfect-reconstruction filter banks implemented by generalized forms of Time Domain Aliasing Cancellation transforms. The derived measures of spectral magnitude and phase may be used in various applications including adaptive bit allocation in perceptual coding systems. An efficient implementation of one particular single-sideband critically-sampled filter bank comprises folding and shuffling blocks of real-valued input signal samples into blocks of complex-valued samples, rotating the complex-valued samples in the complex plane, transforming the rotated samples into transform coefficients, and rotating and shuffling the transform coefficients to form the spectral representation.
Inventors
- 👤 Grant Allen Davidson
- 👤 Stephen Decker Vernon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 08:22
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/66; H04B1/665
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
137 words
A device for processing an input signal comprising input signal samples representing audio information, said device comprising buffer means for receiving a plurality of said input signal samples and forming a sequence of signal sample blocks, spectral means for generating first spectral representations by applying a first single-sideband filter bank to said sequence of signal sample blocks, and generating second spectral representations by applying a second single-sideband filter bank to said sequence of signal sample blocks, phasor means for deriving measures of magnitude and/or phase of spectral components in said audio information in response to said first and second spectral representations, and processor means for processing said first spectral representations to generate an output signal suitable for transmission or storage, wherein said processing is adapted in response to said measures of magnitude and/or phase of spectral components.
Claim 2
Independent Claim
137 words
A device for processing an input signal comprising input signal samples representing audio information, said device comprising buffer means for receiving a plurality of said input signal samples and forming a sequence of signal sample blocks, spectral means for generating first spectral representations by applying a first single-sideband filter bank to said sequence of signal sample blocks, and generating second spectral representations by applying a second single-sideband filter bank to said sequence of signal sample blocks, phasor means for deriving measures of magnitude and/or phase of spectral components in said audio information in response to said first and second spectral representations, and processor means for processing said first spectral representations to generate an output signal suitable for transmission or storage, wherein said processing is adapted in response to said measures of magnitude and/or phase of spectral components.
Claim 3
Dependent Claim
32 words
A device according to claim 1 wherein successive blocks in said sequence of signal sample blocks overlap one another and said first and second single-sideband filter banks are implemented by discrete transforms.
Claim 4
Dependent Claim
16 words
A device according to claim 2 wherein said first and second single-sideband filter banks are critically-sampled.
Claim 5
Dependent Claim
219 words
A device according to claim 3 wherein said first single-sideband filter bank comprises means for folding said input signal samples in a respective signal sample block into a set of first combined samples, means for shuffling the order of said first combined samples into a set of first complex-valued samples, means for applying a first complex rotational function to said first complex-valued samples, means for generating first interim transform coefficients by applying a first transform function to said rotated first complex-valued samples, means for applying a second complex rotation function to said first interim transform coefficients, and means for shuffling said rotated first interim transform coefficients into a respective first spectral representation, and wherein said second single-sideband filter bank comprises means for folding said input signal samples in a respective signal sample block into a set of second combined samples, means for shuffling the order of said second combined samples into a set of second complex-valued samples, means for applying a third complex rotational function to said second complex-valued samples, means for generating second interim transform coefficients by applying a second transform function to said rotated second complex-valued samples, means for applying a fourth complex rotation function to said second interim transform coefficients, and means for shuffling said rotated second interim transform coefficients into a respective second spectral representation.
Claim 6
Dependent Claim
16 words
A device according to claim 1 wherein said first and second single-sideband filter banks are critically-sampled.
Claim 7
Dependent Claim
44 words
A device according to claim 1 wherein said processor means generates an encoded signal by encoding said first spectral representations using a number of bits adaptively allocated in response to said measures of spectral magnitude, and assembles said encoded signal in said output signal.
Claim 8
Independent Claim
165 words
A device for processing two or more input signals comprising input signal samples representing audio information, wherein said device comprises for each respective input signal buffer means for receiving a plurality of said input signal samples representing said respective input signal and forming a sequence of signal sample blocks, spectral means for generating first spectral representations by applying a first single-sideband filter bank to said sequence of signal sample blocks, and generating second spectral representations by applying a second single-sideband filter bank to said sequence of signal sample blocks, and phasor means for deriving measures of magnitude and/or phase of spectral components in said respective input signal in response to said first and second spectral representations, and further comprises processor means for processing first spectral representations for each respective input signal to generate an output signal suitable for transmission or storage, wherein said processing is adapted in response to said measures of magnitude and/or phase of spectral components corresponding to each of said input signals.
Claim 9
Independent Claim
165 words
A device for processing two or more input signals comprising input signal samples representing audio information, wherein said device comprises for each respective input signal buffer means for receiving a plurality of said input signal samples representing said respective input signal and forming a sequence of signal sample blocks, spectral means for generating first spectral representations by applying a first single-sideband filter bank to said sequence of signal sample blocks, and generating second spectral representations by applying a second single-sideband filter bank to said sequence of signal sample blocks, and phasor means for deriving measures of magnitude and/or phase of spectral components in said respective input signal in response to said first and second spectral representations, and further comprises processor means for processing first spectral representations for each respective input signal to generate an output signal suitable for transmission or storage, wherein said processing is adapted in response to said measures of magnitude and/or phase of spectral components corresponding to each of said input signals.
Claim 10
Dependent Claim
37 words
A device according to claim 7 wherein, for a respective input signal, successive blocks in said sequence of signal sample blocks overlap one another and said first and second single-sideband filter banks are implemented by discrete transforms.
Claim 11
Dependent Claim
16 words
A device according to claim 8 wherein said first and second single-sideband filter banks are critically-sampled.
Claim 12
Dependent Claim
219 words
A device according to claim 9 wherein said first single-sideband filter bank comprises means for folding said input signal samples in a respective signal sample block into a set of first combined samples, means for shuffling the order of said first combined samples into a set of first complex-valued samples, means for applying a first complex rotational function to said first complex-valued samples, means for generating first interim transform coefficients by applying a first transform function to said rotated first complex-valued samples, means for applying a second complex rotation function to said first interim transform coefficients, and means for shuffling said rotated first interim transform coefficients into a respective first spectral representation, and wherein said second single-sideband filter bank comprises means for folding said input signal samples in a respective signal sample block into a set of second combined samples, means for shuffling the order of said second combined samples into a set of second complex-valued samples, means for applying a third complex rotational function to said second complex-valued samples, means for generating second interim transform coefficients by applying a second transform function to said rotated second complex-valued samples, means for applying a fourth complex rotation function to said second interim transform coefficients, and means for shuffling said rotated second interim transform coefficients into a respective second spectral representation.
Claim 13
Dependent Claim
16 words
A device according to claim 7 wherein said first and second single-sideband filter banks are critically-sampled.
Claim 14
Dependent Claim
44 words
A device according to claim 7 wherein said processor means generates an encoded signal by encoding said first spectral representations using a number of bits adaptively allocated in response to said measures of spectral magnitude, and assembles said encoded signal in said output signal.
Claim 15
Dependent Claim
96 words
A device according to claim 7 wherein said processor means comprises coupling means for generating a coupled spectral representation by combining spectral components of first spectral representations corresponding to said two or more input signals, side means for generating side-information representing relative spectral magnitude of spectral components represented in said coupled spectral representation, encoding means for generating an encoded signal by encoding said coupled spectral representation using a number of bits adaptively allocated in response to said measures of spectral magnitude, and formatting means for assembling said encoded signal and said side-information into said output signal.
Claim 16
Dependent Claim
25 words
A device according to claim 13 wherein said coupling means adapts said combining in response to said measures of phase so as to avoid cancellation.
Claim 17
Independent Claim
125 words
A method for processing an input signal comprising input signal samples representing audio information, said device comprising receiving a plurality of said input signal samples and forming a sequence of signal sample blocks, generating first spectral representations by applying a first single-sideband filter bank to said sequence of signal sample blocks, and generating second spectral representations by applying a second single-sideband filter bank to said sequence of signal sample blocks, deriving measures of magnitude and/or phase of spectral components in said audio information in response to said first and second spectral representations, and processing said first spectral representations to generate an output signal suitable for transmission or storage, wherein said processing is adapted in response to said measures of magnitude and/or phase of spectral components.
Claim 18
Independent Claim
125 words
A method for processing an input signal comprising input signal samples representing audio information, said device comprising receiving a plurality of said input signal samples and forming a sequence of signal sample blocks, generating first spectral representations by applying a first single-sideband filter bank to said sequence of signal sample blocks, and generating second spectral representations by applying a second single-sideband filter bank to said sequence of signal sample blocks, deriving measures of magnitude and/or phase of spectral components in said audio information in response to said first and second spectral representations, and processing said first spectral representations to generate an output signal suitable for transmission or storage, wherein said processing is adapted in response to said measures of magnitude and/or phase of spectral components.
Claim 19
Dependent Claim
32 words
A method according to claim 15 wherein successive blocks in said sequence of signal sample blocks overlap one another and said first and second single-sideband filter banks are implemented by discrete transforms.
Claim 20
Dependent Claim
16 words
A method according to claim 16 wherein said first and second single-sideband filter banks are critically-sampled.
Claim 21
Dependent Claim
207 words
A method according to claim 17 wherein the applying of said first single-sideband filter bank comprises the steps of folding said input signal samples in a respective signal sample block into a set of first combined samples, shuffling the order of said first combined samples into a set of first complex-valued samples, applying a first complex rotational function to said first complex-valued samples, generating first interim transform coefficients by applying a first transform function to said rotated first complex-valued samples, applying a second complex rotation function to said first interim transform coefficients, and shuffling said rotated first interim transform coefficients into a respective first spectral representation, and wherein the applying of said second single-sideband filter bank comprises the steps of folding said input signal samples in a respective signal sample block into a set of second combined samples, shuffling the order of said second combined samples into a set of second complex-valued samples, applying a third complex rotational function to said second complex-valued samples, generating second interim transform coefficients by applying a second transform function to said rotated second complex-valued samples, applying a fourth complex rotation function to said second interim transform coefficients, and shuffling said rotated second interim transform coefficients into a respective second spectral representation.
Claim 22
Dependent Claim
16 words
A method according to claim 15 wherein said first and second single-sideband filter banks are critically-sampled.
Claim 23
Dependent Claim
43 words
A method according to claim 15 wherein said processing generates an encoded signal by encoding said first spectral representations using a number of bits adaptively allocated in response to said measures of spectral magnitude, and assembles said encoded signal in said output signal.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-03-09 | 2001-09-08 | 2002-03-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-03-09 | 2005-09-08 | 2006-03-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-03-09 | 2009-09-08 | 2010-03-10 | $7700.00 | Window Closed / Lapsed |