EP0424161A2
Expired / Lapsed
EP
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System for coding and decoding an orthogonally transformed audio signal
Assignee: Victor Company of Japan Ltd
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Filing: 1990-10-18
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Granted: —
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Expires: 2010-10-18
Abstract
Abstract A system for coding and decoding an audio signal by using an orthogonal and inverse orthogonal transformation of a block units comprises a coding unit having a circuit (10) for obtaining a power level of the audio signal of a segment unit having a predetermined time interval shorter than the block unit, a circuit (11) for generating a gain control signal from the power level, a circuit (12) for performing a predetermined adaptive gain control responsive to the gain control signal to generate and output the adaptive gain control signal to a decoding unit, thereby performing a pre-treatment, and a coding portion (20) for coding the adaptive gain control signal by using the orthogonal transformation to generate and output a coded signal; and the decoding unit having a decoding portion (30) for decoding the coded signal, dequantizing and inversely and orthogonally transforming a decoded audio signal, and a circuit (13) for performing an inverse gain control for the decoded audio signal responsive to the adaptive gain control signal from the adaptive gain control circuit to reproduce and output an audio signal, thereby performing post-treatment.
Inventors
- 👤 Tokuhiko A-203 Victor Tachibanadai Fuchigami
- 👤 Masaya Konishi
- 👤 Sadahiro Yasura
- 👤 Yasuhiro Yamada
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 08:59
CPC Classifications
G; G10; G10L; G10L19/00; G10L19/02; G10L19/0212
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
133 words
A system for coding and decoding an orthogonally transformed audio signal, having a coding unit for coding an audio signal by an orthogonal transformation of a block unit, and a decoding unit for decoding a coded signal by an inverse orthogonal transformation and reproducing an audio signal, said coding unit comprising; pre-treatment means (15) for obtaining a power level of a segment unit of the audio signal having a time interval shorter than the time interval of said block unit, and for performing a predetermined adaptive gain control corresponding to said power level, so as to obtain a pre-treated audio signal; and coding means (20) for receiving said pre-treatment audio signal, for orthogonally transforming said signal, for quantizing an orthogonally transformed signal, and for coding a quantization signal to output a coded signal.
Claim 2
Independent Claim
133 words
A system for coding and decoding an orthogonally transformed audio signal, having a coding unit for coding an audio signal by an orthogonal transformation of a block unit, and a decoding unit for decoding a coded signal by an inverse orthogonal transformation and reproducing an audio signal, said coding unit comprising; pre-treatment means (15) for obtaining a power level of a segment unit of the audio signal having a time interval shorter than the time interval of said block unit, and for performing a predetermined adaptive gain control corresponding to said power level, so as to obtain a pre-treated audio signal; and coding means (20) for receiving said pre-treatment audio signal, for orthogonally transforming said signal, for quantizing an orthogonally transformed signal, and for coding a quantization signal to output a coded signal.
Claim 3
Dependent Claim
43 words
A system according to claim 1, wherein said pre-treatment means (15) comprises adaptive gain control means (12) for performing said predetermined adaptive gain control by a result obtained from a comparison between a threshold value and said power level of said segment unit.
Claim 4
Dependent Claim
37 words
A system according to claim 2, wherein said adaptive gain control means (12) sets said threshold value at a trailing edge of said input audio signal to a predetermined value lower than one at a leading edge.
Claim 5
Dependent Claim
46 words
A system according to claim 1, wherein said pre-treatment means (15) comprises adaptive gain control means (12) for performing said predetermined adaptive gain control corresponding to a relative value of said power level, which is relative to preceeding and succeeding segment units of said segment unit.
Claim 6
Dependent Claim
29 words
A system according to claim 1, wherein said pre-treatment means (15) comprises adaptive gain control means (12) for performing said predetermined adaptive gain control non-linearly at a segment boundary.
Claim 7
Dependent Claim
76 words
A system according to claim 1, wherein said pre-treatment means (15) comprises adaptive gain control means (12) for performing said predetermined adaptive gain control corresponding to a relative value of said power level, which is relative to preceeding and succeeding segment units of said segment unit, and for performing said predetermined adaptive gain control corresponding to a relative value of said power level, which is relative to preceeding and succeeding segment units of said segment unit.
Claim 8
Dependent Claim
27 words
A system according to claim 2, wherein said adaptive gain control means (12) sets a plurality of threshold values at a trailing edge of said audio signal.
Claim 9
Independent Claim
215 words
A system for coding and decoding an orthogonal audio signal, having a coding unit for coding an audio signal by an orthogonal transformation of a block unit, and a decoding unit for decoding a coded signal by an inverse orthogonal transformation and reproducing an audio signal; said coding unit comprising means (10) for obtaining a power level of an input audio signal of a segment unit having a predetermined time interval shorter than said block unit, means (11) for generating a gain control signal on the basis of said power level, means (12) for performing a predetermined adaptive gain control responsive to said gain control signal so as to perform a pre-treatment of said audio signal, thereby outputting said gain control signal to said decoding unit, and a coding portion (20) for coding said gain control signal after said pre-treatment to generate a coded signal and for outputting said coded signal to said decoding unit; and said decoding unit comprising a decoding portion (30) for decoding said coded signal into a decoded audio signal by using an inversely orthogonal transformation, and means (17) for post-treating said decoded audio signal responsive to said gain control signal output from said adaptive gain control means (12) by inverse gain control so as to output a reproduced audio signal.
Claim 10
Independent Claim
215 words
A system for coding and decoding an orthogonal audio signal, having a coding unit for coding an audio signal by an orthogonal transformation of a block unit, and a decoding unit for decoding a coded signal by an inverse orthogonal transformation and reproducing an audio signal; said coding unit comprising means (10) for obtaining a power level of an input audio signal of a segment unit having a predetermined time interval shorter than said block unit, means (11) for generating a gain control signal on the basis of said power level, means (12) for performing a predetermined adaptive gain control responsive to said gain control signal so as to perform a pre-treatment of said audio signal, thereby outputting said gain control signal to said decoding unit, and a coding portion (20) for coding said gain control signal after said pre-treatment to generate a coded signal and for outputting said coded signal to said decoding unit; and said decoding unit comprising a decoding portion (30) for decoding said coded signal into a decoded audio signal by using an inversely orthogonal transformation, and means (17) for post-treating said decoded audio signal responsive to said gain control signal output from said adaptive gain control means (12) by inverse gain control so as to output a reproduced audio signal.
References Cited (Backward Citations)
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