EP 0000990 A1 19790307 - Unbalanced/balanced converter circuits.
Title (en)
Unbalanced/balanced converter circuits.
Title (de)
Schaltung zum Übergang von Unsymmetrie auf Symmetrie.
Title (fr)
Circuit de conversion dissymétrique-symétrique.
Publication
Application
Priority
GB 3451077 A 19770817
Abstract (en)
Unbalanced/balanced converter circuit in which a first circuit (T1, T2) of controllable impedance is connected between a first supply terminal (earth) and a first balanced terminal (A-leg), a second circuit (T3, T4) of controllable impedance is connected between a second supply terminal (-48V d.c.) and a second belanced terminal (B-leg), and a control circuit (R, R2, A1) is connected to monitor any departure from balance of the potentials of the first and second balanced input/output terminals and to simultaneously change the impedances of the first and second circuits (T1, T2 and T3, T4 resp.) of controllable impedance in opposite directions to restore the potentials to balance. A first unbalanced terminal (X) is connected (via C6) to one balanced terminal (A-leg) and a second unbalanced terminal is connected to a common point (earth). <??>A principal use of the invention is balance/unbalanced conversion of a subscriber's telephone line.
IPC 1-7
IPC 8 full level
H03H 7/42 (2006.01); H03H 11/32 (2006.01); H04Q 3/42 (2006.01); H04B 1/58 (2006.01); H04M 19/00 (2006.01)
CPC (source: EP US)
H03H 7/42 (2013.01 - EP US); H03H 11/32 (2013.01 - EP US); H04B 1/583 (2013.01 - EP US); H04M 19/005 (2013.01 - EP US)
Citation (search report)
- US 3955052 A 19760504 - ORBACH SHELOMO
- [P] FR 2373201 A1 19780630 - DEUTSCHE TELEPHONWERK KABEL [DE]
Designated contracting state (EPC)
DE FR NL SE
DOCDB simple family (publication)
EP 0000990 A1 19790307; AU 3891478 A 19800221; BR 7805280 A 19790417; DE 2857160 A1 19800306; FR 2426366 A1 19791214; GB 2003003 A 19790228; GB 2003003 B 19820217; IT 1105455 B 19851104; IT 7850750 A0 19780816; JP S5452953 A 19790425; NL 7815016 A 19791031; PT 68425 A 19780901; SE 7907125 L 19790827; US 4203009 A 19800513; ZA 784547 B 19790829
DOCDB simple family (application)
EP 78300250 A 19780815; AU 3891478 A 19780815; BR 7805280 A 19780816; DE 2857160 A 19780815; FR 7913436 A 19790525; GB 7833685 A 19780817; IT 5075078 A 19780816; JP 10043478 A 19780817; NL 7815016 A 19780815; PT 6842578 A 19780816; SE 7907125 A 19790827; US 93269678 A 19780810; ZA 784547 A 19780810