Telephonic communications – Subscriber line or transmission line interface – Hybrid circuit
Patent
1985-07-29
1988-12-06
Ng, Jin F.
Telephonic communications
Subscriber line or transmission line interface
Hybrid circuit
379413, H04B 158
Patent
active
047899999
ABSTRACT:
There is disclosed a line circuit for connecting a subscriber set to a switching facility to obtain an impedance match. The subscriber set is connected to first and second subscriber terminals by a two-wire line which presents a complex terminating impedance to said switching facility. A constant current source is connected between the first and second terminals for supplying the subscriber set with a constant direct current. There is a control current source coupled between the first and second terminals for supplying the subscriber set with an alternating current with the control current source having a control input. The first and second terminals are connected to respective first and second inputs of a differential amplifier whose output is coupled to a transmit line. The control input of the control current source is coupled to a receive line. In order to provide an impedance match, there is a complex impedance which is coupled between the output of the differential amplifier and the control input of the current source. The receive terminal is coupled to one input of the differential amplifier by a first resistor. The first and second inputs of the differential amplifier are coupled to the first and second subscriber terminals via separate resistors of equal value with the ratio of the first resistor to one of the first and second resistors selected to provide an impedance match for said subscriber line as connected to said switching facility.
REFERENCES:
patent: 3855430 (1974-12-01), Colardelle et al.
patent: 3970805 (1976-07-01), Thomas
patent: 4064377 (1977-12-01), Regan
patent: 4278847 (1981-07-01), Wortman
patent: 4319093 (1982-03-01), Bars
patent: 4351060 (1982-09-01), Treiber
patent: 4387273 (1983-06-01), Chea, Jr.
patent: 4476350 (1984-10-01), Aull et al.
patent: 4571460 (1986-02-01), Rosenbaum et al.
patent: 4600811 (1986-07-01), Hayashi et al.
patent: 4604741 (1986-08-01), Barsellotti
patent: 4631359 (1986-12-01), Johansson et al.
patent: 4631360 (1986-12-01), Johansson et al.
patent: 4631366 (1986-12-01), Takato et al.
Ericsson Review; No. 4, 1983, vol. 60, "Line Circuit Component SLIC for AXE 10", p. 192.
Meschkat Peter
Zanzig Jurgen
ALCATEL N.V.
Ng Jin F.
Vaas R.
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