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Patent US5058153A successfully refreshed from Google Patents.
US5058153A
Expired / Lapsed
US
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Noise mitigation and mode switching in communications terminals such as telephones
Assignee: Nortel Networks Ltd
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Filing: 1989-12-27
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Granted: 1991-10-15
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Expires: 2009-12-27
Abstract
Abstract A circuit to improve noise mitigation and mode switching in telephony, wherein the noise-floor level is continuously estimated by comparing its stored current value to the signal level value and substituting the latter for the former if it is less than the former.
Inventors
- 👤 Edward C. Carew
- 👤 Roland T. Lockhart
- 👤 Sean G. Brophy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 09:52
CPC Classifications
H; H04; H04M; H04M9/00; H04M9/08; H04M9/085
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
144 words
A circuit for controlling a telecommunications terminal between three states: a transmit state, a receive state, and a quiescent state, wherein voice signals are transmitted and received to and from a remote terminal, comprising; an acousto-electric transducer providing signals for transmission to said remote terminal through a transmit variolosser; an electro-acoustic transducer providing audible signals received from said remote terminal through a receive variolosser; first envelope detection means for detecting the signals from said acousto-electric transducer for providing a microphone signal value; second envelope detection means at the output of said transmit variolosser; storage means registering a current noise signal value; and means for substituting said microphone signal value into said storage means in response to a comparison indicating said microphone signal value being less than said current noise signal value, whereby said microphone signal value becomes a new, lower, current noise signal value.
Claim 2
Dependent Claim
144 words
A circuit for controlling a telecommunications terminal between three states: a transmit state, a receive state, and a quiescent state, wherein voice signals are transmitted and received to and from a remote terminal, comprising; an acousto-electric transducer providing signals for transmission to said remote terminal through a transmit variolosser; an electro-acoustic transducer providing audible signals received from said remote terminal through a receive variolosser; first envelope detection means for detecting the signals from said acousto-electric transducer for providing a microphone signal value; second envelope detection means at the output of said transmit variolosser; storage means registering a current noise signal value; and means for substituting said microphone signal value into said storage means in response to a comparison indicating said microphone signal value being less than said current noise signal value, whereby said microphone signal value becomes a new, lower, current noise signal value.
Claim 3
Dependent Claim
33 words
The circuit for controlling a telecommunications terminal as defined in claim 1, further comprising third envelope detection means at the input of a receive variolosser for varying path gain of received voice signals.
Claim 4
Dependent Claim
23 words
The circuit for controlling a telecommunications terminal as defined in claim 2, further comprising microprocessor means for controlling said transmit and receive variolossers.
Claim 5
Dependent Claim
41 words
The circuit for controlling a telecommunications terminal as defined in claim 3, further comprising program means in said microprocessor for comparing said microphone signal value to said current noise signal value to decide if the former is less than the latter.
Claim 6
Dependent Claim
31 words
The circuit for controlling a telecommunications terminal as defined in claim 4, further comprising program means in said microprocessor for periodically incrementing said current noise signal value by a predetermined amount.
Claim 7
Dependent Claim
33 words
The circuit for controlling a telecommunications terminal as defined in claim 5, wherein the periodical incrementing of the current noise signal value occurs every few seconds by an amount of a few decibels.
Claim 8
Dependent Claim
21 words
The circuit for controlling a telecommunications terminal as defined in claim 6, wherein said few seconds is less than ten seconds.
Claim 9
Dependent Claim
21 words
The circuit for controlling a telecommunications terminal as defined in claim 6, wherein said few decibels is less than five decibels.
Claim 10
Dependent Claim
30 words
The circuit for controlling a telecommunications terminal as defined in claim 6, wherein said few seconds is less than ten seconds, and said few decibels is less than five decibels.
Claim 11
Dependent Claim
30 words
The circuit for controlling a telecommunications terminal as defined in claim 9, wherein said few seconds is one to six seconds, and said few decibels is one-half to two decibels.
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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) | 1994-10-14 | 1995-04-15 | 1995-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-10-14 | 1999-04-15 | 1999-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-10-14 | 2003-04-15 | 2003-10-15 | $7700.00 | Window Closed / Lapsed |