Patent US3855430A successfully refreshed from Google Patents.
US3855430A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic hybrid circuit for two-wire to four-wire interconnection
Assignee: Alcatel Lucent NV
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Filing: 1972-11-15
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Granted: 1974-12-17
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Expires: 1992-11-15
Abstract
Abstract An electronic hybrid circuit is disclosed for two-wire to fourwire conversion. Two integrated circuit differential amplifiers are used to provide transmission in each direction. Interconnections are possible between the amplifiers to insure cancellation of reflections from signals traveling in opposite directions.
Inventors
- 👤 P Lerouge
- 👤 J Colardelle
- 👤 P Girard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 13:57
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/38; H04B1/40; H04B1/54; H04B1/58; H04B1/586; H04M; H04M19/00; H04M19/001; H04M19/005
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
202 words
An electronic two-wire to four-wire conversion circuit comprising a pair of input terminals connected to a balanced subscriber''s line which provides a first variable voltage for data transmission in a first direction and which receives a second variable voltage for data transmission in the reverse direction, a receive terminal pair connected via first transmission means to said input terminals to transmit data signals toward the reverse direction, said first transmission means including first and second operational amplifiers connected to the receive terminal pair and to each other to convert unbalanced data signals applied to the receive terminal pair into balanced signals appearing across the input terminals, a transmit terminal pair connected via second transmission means to said input terminals to transmit data signals toward the first direction, said second transmission means including a differential amplifier connected across the pair of input terminals and connected in series with a current generator having an output connected to the transmit terminal pair, said second transmission means converting balanced input signals into unbalanced signals, and third means coupled between the output of the first operational amplifier and the non-inverting input of the differential amplifier for preventing signal reflections from the reverse direction to the first direction.
Claim 2
Dependent Claim
202 words
An electronic two-wire to four-wire conversion circuit comprising a pair of input terminals connected to a balanced subscriber''s line which provides a first variable voltage for data transmission in a first direction and which receives a second variable voltage for data transmission in the reverse direction, a receive terminal pair connected via first transmission means to said input terminals to transmit data signals toward the reverse direction, said first transmission means including first and second operational amplifiers connected to the receive terminal pair and to each other to convert unbalanced data signals applied to the receive terminal pair into balanced signals appearing across the input terminals, a transmit terminal pair connected via second transmission means to said input terminals to transmit data signals toward the first direction, said second transmission means including a differential amplifier connected across the pair of input terminals and connected in series with a current generator having an output connected to the transmit terminal pair, said second transmission means converting balanced input signals into unbalanced signals, and third means coupled between the output of the first operational amplifier and the non-inverting input of the differential amplifier for preventing signal reflections from the reverse direction to the first direction.
Claim 3
Dependent Claim
60 words
A circuit as claimed in claim 1, in which the means for preventiNg signal reflections from the reverse direction to the first direction includes a resistor coupled directly between the output of the first operational amplifier and the non-inverting input of the differential amplifier to null any reflection of the signals transmitted in the reverse direction toward the first direction.
Claim 4
Dependent Claim
49 words
A circuit as claimed in claim 1, in which the pair of input terminals are connected via capacitors to the first and second transmission means to enable a DC voltage to be applied to the subscriber''s line and to isolate said first and second means from said DC voltage.
Claim 5
Dependent Claim
119 words
A circuit as claimed in claim 1, in which the first operational amplifier converts incoming data current appearing on the receive terminal pair into an output voltage at the output terminal of the first operational amplifier in phase opposition with said incoming data current, the second operational amplifier is coupled as a voltage inverter to said output terminal to deliver at its output terminal a voltage in phase opposition with respect to its input voltage, whereby voltages at the output terminals of said first and second operational amplifiers are of equal amplitude and in phase opposition, and means coupling said output terminals respectively to the pair of input terminals to enable the completion of transmission in the reverse direction.
Claim 6
Dependent Claim
99 words
A circuit as claimed in claim 1, in which the pair of input terminals are connected via capacitors through corresponding terminals to the first and second transmission means, the differential amplifier includes input terminals coupled through resistors of equal value to the corresponding terminals to provide an unbalanced output at an output terminal, the current generator is an operational amplifier having an inverting input coupled to the output terminal of the differential amplifier and a non-inverting input connected to the transmit terminal pair, whereby the current generator delivers data current via the transmit terminal pair to a switching network.
Claim 7
Dependent Claim
44 words
A circuit as claimed in claim 5, in which an additional resistor is coupled between the output of the first operational amplifier and the inverting input of the differential amplifier to avoid reflection of signals transmitted in the reverse direction toward the first direction.
Claim 8
Dependent Claim
49 words
A circuit as claimed in claim 1, in which the current generator includes a differential amplifier, the differential amplifier includes a negative feedback network coupling its output and its inverting input terminal, and the differential amplifier includes a positive feedback network coupling its output and its non-inverting feedback network.
Claim 9
Dependent Claim
56 words
A circuit as claimed in claim 7, in which a load resistance is coupled to the non-inverting input of said differential amplifier, and the value of the current supplied to said load resistance is a function of the input voltage and input resistance to the differential amplifier and independent of the value of the load resistance.
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) | 1977-12-16 | 1978-06-17 | 1978-12-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-16 | 1982-06-17 | 1982-12-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-16 | 1986-06-17 | 1986-12-17 | $7700.00 | Window Closed / Lapsed |