Telephone station repeater
AssigneeBell Telephone Laboratories, Incorporated
InventorKenneth Erwin Stiefel
Life of this patent
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Abstract
A telephone station repeater is disclosed which will provide bidirectional gain in a long telephone loop at the customer's station. The repeater is powered from the central office battery over the loop and provides gain with very small power consumption and virtually no power consumption when not in use. The station repeater comprises a negative impedance amplifier including a shunt negative impedance, a series negative impedance and an autotransformer connected in a .pi. configuration. The shunt converter is disconnected when the telephone set is on-hook. The autotransformer provides impedance matching to the telephone set.
Claims9
A negative impedance bidirectional amplifier for insertion at the subscriber end of a telephone line, said amplifier comprising:
- a shunt negative impedance converter;
- a series negative impedance converter;
- and
- a shunt autotransformer;
- said negative impedance converters and said autotransformer being connected in a .pi. configuration with respect to said telephone line.
A telephone station repeater energized from the central office battery over a long telephone loop, said repeater comprising:
- a shunt negative impedance converter,
- a current responsive switch for connecting said shunt negative impedance converter across said telephone loop;
- a series negative impedance converter connected to one end to said current responsive switch;
- an autotransformer connected at the other end of said series negative impedance converter and in shunt with said telephone loop;
- and
- at least one telephone set connected across a portion of the winding of said autotransformer.
Dependencies are inferred from the claim text.