Patent US4241236A successfully refreshed from Google Patents.
US4241236A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Noise range indicating system
Assignee: AT&T Inc
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Filing: 1978-11-02
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Granted: 1980-12-23
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Expires: 1998-11-02
Abstract
Abstract A hands-free telephone system is disclosed utilizing an infrared transmitter and receiver to permit wireless speech transmission. The transmitter uses frequency modulation imposed on the infrared signal and includes carrier shift signaling arrangements for indicating a low battery condition and transmitter turn-off. The receiver utilizes a noise detection circuit for permitting remote turn-on, for squelching noise in the voice path, and for feeding an alerting signal to a loudspeaker to indicate that the received signal is excessively noisy. The portable transmitter must then be moved or redirected to provide a better line-of-sight signaling path.
Inventors
- 👤 Donald H. Nash
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 08:28
CPC Classifications
H; H04; H04M; H04M1/00; H04M1/72; H04M1/725; H04M1/72502; H04M1/72516; H04M1/737
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
76 words
A wireless audio transmission system for use within an enclosed space and including a portable wireless transmitter, a stationary receiver, and a loudspeaker, CHARACTERIZED BY a noise detector in said receiver for detecting the noise level in signals transmitted from said transmitter to said receiver, and a noise enhancement circuit for applying at least a portion of said noise to said loudspeaker wherein said noise is supplied from said noise detector to said noise enhancement circuit.
Claim 2
Dependent Claim
76 words
A wireless audio transmission system for use within an enclosed space and including a portable wireless transmitter, a stationary receiver, and a loudspeaker, CHARACTERIZED BY a noise detector in said receiver for detecting the noise level in signals transmitted from said transmitter to said receiver, and a noise enhancement circuit for applying at least a portion of said noise to said loudspeaker wherein said noise is supplied from said noise detector to said noise enhancement circuit.
Claim 3
Dependent Claim
25 words
The wireless transmission system according to claim 1 further CHARACTERIZED BY said transmitter and said receiver being adapted to operate in the infrared frequency range.
Claim 4
Dependent Claim
23 words
The wireless transmission system according to claim 1 further CHARACTERIZED BY control circuits (3) for interconnecting said transmission system with a telephone line.
Claim 5
Dependent Claim
56 words
The wireless transmission system according to claim 1 wherein said noise enhancement circuit is CHARACTERIZED BY a noise amplifier, a variable impedance, means connecting the output of said noise detector through said variable impedance and said noise amplifier to said loudspeaker, and means responsive to the output of said noise detector for varying said variable impedance.
Claim 6
Dependent Claim
31 words
The wireless transmission system according to claim 4 wherein said varying means is CHARACTERIZED BY a threshold detector for setting a noise level threshold above which said noise signal is enhanced.
Claim 7
Dependent Claim
68 words
A hands-free telephone station system comprising a portable transmitter for wireless transmission, a stationary receiver connectable to a telephone line, a loudspeaker, a noise detector responsive to the noise level in signals received from said transmitter, and noise connecting means responsive to said detector for applying a portion of said noise to said loudspeaker wherein said noise is supplied from said noise detector to said noise enhancement circuit.
Claim 8
Dependent Claim
68 words
A hands-free telephone station system comprising a portable transmitter for wireless transmission, a stationary receiver connectable to a telephone line, a loudspeaker, a noise detector responsive to the noise level in signals received from said transmitter, and noise connecting means responsive to said detector for applying a portion of said noise to said loudspeaker wherein said noise is supplied from said noise detector to said noise enhancement circuit.
Claim 9
Dependent Claim
28 words
The hands-free telephone station system according to claim 6 wherein said transmitter and said receiver include, respectively, means for transmitting and receiving signals in the infrared frequency range.
Claim 10
Dependent Claim
28 words
The hands-free telephone station system according to claim 6 further including a telephone line, and means for selectively connecting said receiver and said loudspeaker to said telephone line.
Claim 11
Dependent Claim
55 words
The hands-free telephone station system according to claim 6 wherein said noise connecting means comprises a noise amplifier, a variable impedance, means connecting the output of said noise detector through said variable impedance and said noise amplifier to said loudspeaker, and means responsive to the output of said noise detector for varying said variable impedance.
Claim 12
Dependent Claim
31 words
The hands-free telephone station system according to claim 9 further including a threshold level detector responsive to said noise detector output to enable said variable impedance only above a preselected threshold.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-12-23 | 1984-06-23 | 1984-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-12-23 | 1988-06-23 | 1988-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-12-23 | 1992-06-23 | 1992-12-23 | $7700.00 | Window Closed / Lapsed |