Patent US4609788A successfully refreshed from Google Patents.
US4609788A
Expired / Lapsed
US
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Digital voice transmission having improved echo suppression
Assignee: Racal Data Communications Inc
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Filing: 1983-03-01
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Granted: 1986-09-02
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Expires: 2003-03-01
Abstract
Abstract A digital communication apparatus with improved echo suppression includes a circuit for detecting the gain of a far talker signal and a circuit for detecting the gain of a near talker signal. These gains are compared and echo suppression is accomplished by suppressing the lesser of the two gains.
Inventors
- 👤 William J. Miller
- 👤 Chun C. Lu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:46
CPC Classifications
H; H04; H04B; H04B3/00; H04B3/02; H04B3/20
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
107 words
A digital communication apparatus for transmitting and receiving a compressed digital representation of speech produced by a near talker and a far talker respectively, said compressed digital representation of speech including a coded gain parameter related to speech energy, said apparatus comprising: transmission gain detection means for reading the gain parameter of said near talker's compressed digital representation of speech; receiver gain detection means for reading the gain parameter of said far talker's compressed digital representation of speech; means for detection which of said near talker and far talker gain parameters has a lesser value, and for reducing the gain parameter detected to have the lesser value.
Claim 2
Dependent Claim
107 words
A digital communication apparatus for transmitting and receiving a compressed digital representation of speech produced by a near talker and a far talker respectively, said compressed digital representation of speech including a coded gain parameter related to speech energy, said apparatus comprising: transmission gain detection means for reading the gain parameter of said near talker's compressed digital representation of speech; receiver gain detection means for reading the gain parameter of said far talker's compressed digital representation of speech; means for detection which of said near talker and far talker gain parameters has a lesser value, and for reducing the gain parameter detected to have the lesser value.
Claim 3
Independent Claim
107 words
A method of echo suppression in a digital communication link having near and far ends, said digital communication link communicating a compressed digital representation of speech produced by a near talker and a far talker, said compressed digital representation of speech including a coded gain parameter related to speech energy, the method comprising the steps of: at said first end, determining which of said gain parameters has a first lesser value and reducing said gain parameter having said first lesser value; and at said second end, determining which of said gain parameters has a second lesser value and reducing said gain parameter having said second lesser value.
Claim 4
Independent Claim
107 words
A method of echo suppression in a digital communication link having near and far ends, said digital communication link communicating a compressed digital representation of speech produced by a near talker and a far talker, said compressed digital representation of speech including a coded gain parameter related to speech energy, the method comprising the steps of: at said first end, determining which of said gain parameters has a first lesser value and reducing said gain parameter having said first lesser value; and at said second end, determining which of said gain parameters has a second lesser value and reducing said gain parameter having said second lesser value.
References Cited (Backward Citations)
US3821494A
Cited
US4051332A
Cited
US4028506A
Cited
US4002854A
Cited
US4005276A
Cited
US4016557A
Cited
US4031338A
Cited
US4131767A
Cited
US4074086A
Cited
CA1109133A
Cited
CA1112383A
Cited
US4368360A
Cited
US4165449A
Cited
US4230906A
Cited
US4213097A
Cited
US4490582A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-09-01 | 1990-03-03 | 1990-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-09-01 | 1994-03-03 | 1994-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-09-01 | 1998-03-03 | 1998-09-02 | $7700.00 | Window Closed / Lapsed |