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 Title: |
US6252968:
Acoustic quality enhancement via feedback and equalization for mobile multimedia systems
[ Derwent Title ]
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| Country: |
US United States of America
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| Inventor: |
Narasimhan, Anand; Beverly Hills, CA
Ramaswamy, Ganesh Nachiappa; Ossining, NY
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| Assignee: |
International Business Machines Corp., Armonk, NY
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| Published / Filed: |
2001-06-26
/ 1997-09-23
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| Application Number: |
US1997000935979
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| IPC Code: |
Advanced:
H04R 29/00;
H04S 7/00;
Core:
more...
IPC-7:
H03G 5/00;
H04R 29/00;
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| ECLA Code: |
H04R29/00; H04S7/00E; T04R29/00L;
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| U.S. Class: |
Current:
381/103;
381/056;
381/059;
381/102;
Original:
381/103;
381/102;
381/056;
381/059;
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| Field of Search: |
381/103,102,56,58,59,98,96
379/388,389
700/094
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| Priority Number: |
| 1997-09-23 |
US1997000935979 |
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| Abstract: |
A method of enhancing the audio quality in a reproduction medium having unknown characteristics. With this method a predetermined finite set of single frequency tones are generated and these tones are then passed through the reproduction medium to generate an output signal, which in turn is passed through a set of sub-band filters. Each of the sub-band filters pass at least a frequency corresponding to one of the tones in the set of tones. The characteristics of the reproduction medium is then estimated as a result of passing the output signal through the set of sub-band filters. Based on the estimated characteristics of the reproduction medium, a set of sub-band inverse filters are constructed. Finally before passing the audio signal through the reproduction medium the signal is passed through the set of inverse filters to improve the quality of the audio signal after it passes through the reproduction medium.
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| Attorney, Agent or Firm: |
Cameron, Douglas W. ;
Doughtery, Anne Vachon ;
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| Primary / Asst. Examiners: |
Mei, Xu;
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| Maintenance Status: |
E2 Expired Check current status
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| INPADOC Legal Status: |
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| Family: |
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First Claim:
Show all 3 claims |
Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:
1. A method of rapidly enhancing audio quality of an input audio signal in a portable computing system having limited resources and having a reproduction medium with unknown characteristics, said method comprising:
- a. generating a predetermined finite set of M single frequency tones;
- b. passing said set of tones through said reproduction medium to generate a subsequent output signal;
- c. passing said subsequent output signal through a set of sub-band filters, each of the sub-band filters passing at least a frequency corresponding to one of the M tones;
- d. estimating the unknown characteristics of said reproduction medium by examining outputs of each of said sub-band filters after passing said subsequent output signal through said medium to produce gain estimates;
- e. dynamically constructing a set of sub-band inverse filters to compensate for the estimated characteristics of the reproduction medium; and
- f. before passing an input audio signal through said reproduction medium, passing said audio signal through said inverse filters, thereby improving the audio quality after the audio signal passes through said reproduction medium.
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| Background / Summary: |
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| Drawing Descriptions: |
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| Description: |
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| Forward References: |
Show 5 U.S. patent(s) that reference this one
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