Patent US3889072A successfully refreshed from Google Patents.
US3889072A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Bi-directional amplification apparatus
Assignee: Nokia of America Corp
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Filing: 1973-10-19
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Granted: 1975-06-10
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Expires: 1993-10-19
Abstract
Abstract A voice frequency amplification apparatus is disclosed for use in telecommunications applications such as a trunk circuit interfacing between a single wire speech path and another line which may be a two-wire line to an outside area such as a remote central office. Within the apparatus, the speech path for each direction includes a difference amplifier. The uni-directional characteristics of the amplifiers provide one form of isolation of signals in one path from the signals in the other. The interconnection of the two paths provides relative balance between the input path and the amplifier to provide phase reversal and cancellation of unwanted reflection signals. Within the apparatus, inherent D.C. stability is provided by the interrelationship and biasing of the amplifiers and the speech paths while A.C. stability is provided by a balance between the gain and the amplifier impedance.
Inventors
- 👤 Alan Stewart
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 21:04
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/62; H04; H04B; H04B1/00; H04B1/38; H04B1/40; H04B1/54; H04B1/58; H04B1/586; H04M; H04M3/00; H04M3/40
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
241 words
A two-wire, bi-directional voice amplification apparatus adapted to transmit and receive voice frequency signals between a single wire, ground return line coupled to one end of the apparatus and a line coupled to the other end, said apparatus comprising a single wire path for each direction of transmission with both said single wire paths joined to the respective lines at the ends of said apparatus, amplifying means in each path, each said amplifying means including a first and a second input and a single output, means biasing each said amplifying means to a difference amplifier configuration for providing unidirectional signal passage therethrough, the first input to a first of said amplifying means being coupled to said one end of the apparatus and the first input to a second of said amplifying means coupled to the line at the other end, respective feedback networks coupling the second input of each of said amplifying means to the output of the respective other amplifying means for cancelling signals fed back from the respective outputs through the feedback paths, means balancing the first input of said first amplifying means against the second input to cause amplification of signals transmitted to said inputs, and means in the feedback network from the output of said first amplifying means for attenuating AC signals directed to the input to which said network is coupled to prevent noise due to voice frequency alternating current signals and oscillation in said apparatus.
Claim 2
Dependent Claim
241 words
A two-wire, bi-directional voice amplification apparatus adapted to transmit and receive voice frequency signals between a single wire, ground return line coupled to one end of the apparatus and a line coupled to the other end, said apparatus comprising a single wire path for each direction of transmission with both said single wire paths joined to the respective lines at the ends of said apparatus, amplifying means in each path, each said amplifying means including a first and a second input and a single output, means biasing each said amplifying means to a difference amplifier configuration for providing unidirectional signal passage therethrough, the first input to a first of said amplifying means being coupled to said one end of the apparatus and the first input to a second of said amplifying means coupled to the line at the other end, respective feedback networks coupling the second input of each of said amplifying means to the output of the respective other amplifying means for cancelling signals fed back from the respective outputs through the feedback paths, means balancing the first input of said first amplifying means against the second input to cause amplification of signals transmitted to said inputs, and means in the feedback network from the output of said first amplifying means for attenuating AC signals directed to the input to which said network is coupled to prevent noise due to voice frequency alternating current signals and oscillation in said apparatus.
Claim 3
Dependent Claim
15 words
A system as claimed in claim 1, wherein each said amplifier comprises an operational amplifier.
Claim 4
Dependent Claim
228 words
A two-wire system for bi-directionally transmitting voice frequency signals between a single wire, ground return switching network at one end of said system and a line connected to signal transmitting and receiving means at the other end of said system, said system comprising a first single wire path for one direction of voice frequency transmission and a second single wire path for the other direction of transmission with said paths being joined at the ends thereof to form a closed loop, an operational amplifier in each path biAsed to perform as a difference amplifier, a first of said amplifiers being disposed in the path for one direction to render said path unidirectional in transmission therethrough, and said second amplifier disposed in the other path to render said path unidirectional, each said amplifier having two inputs and an output, one of said inputs and the output of an amplifier comprising one transmission path and one input and the output of the other amplifier comprising the transmission path for the other direction, the other input of each amplifier comprising a feedback network from the output of the other amplifier, and means in a feedback path for said one direction for attenuating voice frequency signals reflected from the output of the other amplifier to cause cancellation of the reflected signals within the amplifier to which the feedback path forms an input.
Claim 5
Dependent Claim
228 words
A two-wire system for bi-directionally transmitting voice frequency signals between a single wire, ground return switching network at one end of said system and a line connected to signal transmitting and receiving means at the other end of said system, said system comprising a first single wire path for one direction of voice frequency transmission and a second single wire path for the other direction of transmission with said paths being joined at the ends thereof to form a closed loop, an operational amplifier in each path biAsed to perform as a difference amplifier, a first of said amplifiers being disposed in the path for one direction to render said path unidirectional in transmission therethrough, and said second amplifier disposed in the other path to render said path unidirectional, each said amplifier having two inputs and an output, one of said inputs and the output of an amplifier comprising one transmission path and one input and the output of the other amplifier comprising the transmission path for the other direction, the other input of each amplifier comprising a feedback network from the output of the other amplifier, and means in a feedback path for said one direction for attenuating voice frequency signals reflected from the output of the other amplifier to cause cancellation of the reflected signals within the amplifier to which the feedback path forms an input.
Claim 6
Dependent Claim
65 words
A transmission system as claimed in claim 3, wherein there is a transformer with one winding thereof coupled to the joinder of said single wire paths at said other end of said system, said transformer disposed to invert thereacross signals from said other end directed to the respective two paths, and means for feeding said inverted signals to the respective inputs of said second amplifier.
Claim 7
Dependent Claim
40 words
A system as claimed in claim 3 wherein, said other end line comprises a single-wire ground return line, and in which there is balancing means coupled to each feedback network for balancing input signals for cancellation in the respective amplifiers.
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) | 1978-06-09 | 1978-12-09 | 1979-06-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-09 | 1982-12-09 | 1983-06-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-09 | 1986-12-09 | 1987-06-10 | $7700.00 | Window Closed / Lapsed |